I get this indication of changes in culture over time from "Rise of the Greek Epic, copyright 1911 by Gilbert Murray, based on a series of lectures he gave at Harvard. I read the book in my local library, but I see it's online as a google book: The rise of the Greek epic: being a course of lectures delivered at Harvard ... - Gilbert Murray - Google Books
Changes in houses. Originally, houses were one room halls. In the evening, guests were sent outside to sleep on the pourch so
the householder and his wife could have a little privacy. That's where Telemachus stays when he visits Nestor and Menelaos, (Od book 3, lines 395-406, and book 4 lines 296 to 307. and where Odysseus stays when he's a guest of Alcinous( Od book 7, lines 228-347). In the Illiad, when Hector visits Paris in
his home, (Il book 6, lines 321 ff), he finds Paris cleaning his armor, and Helen and her maids spinning, all in the one room hall. In the story of Ares' adultery with Hephaistos' wife, Aphrodite, (Od book 8,lines 304-325), Hephaistos catches the adulterers in a trap, and the other gods seem them trapped in bed in a web from the doorway outside the house.
In the Illiad, book 24, lines 643-650, the poet is not aware of this universal custom, and gives feeble excuses for Achilles (rudely, in the poet's view) making Priam sleep on the pourch. Also, not aware of the custom, in book 4 of the Odyssey, Helen and Menelaos go to sleep in the hall, yet in the morning Helen comes out of her "fragrant, high-roofed bower". Penelope slept in "upper chambers". Classical Greeks pictured many roomed palaces rather than the one room halls of the "Heroic" period.
Changes in worship. In the original story, altars were in the open air. (Il 1, 446, Il 2,line 305, Il 8, 238ff, Od 6, 162)
In book IL 1, line 39, and in Il book 6 there are descriptions of indoor temples- which the classical Greeks had but the original Homeric characters did not.
Changes in armor. The Athenians pictured warriors fighting in phalanx formation, with Iron swords and spears, with bronze breastplates, bronze helmets, and bronze greaves. The original "Heroic" characters had bronze swords, but leather helmets and chest protectors, and had oxhide shields or used the skins of animals. In Il 4, 448, Il Il 7, 62, Il 20, 156.
The combatants are described as fighting in phalanx formation, as the Athenians did at Marathon. Il 3, 1-9, Il 4, 427-432. In Il 13, 801 the Trojans are also supposedly fighting in phalanx formation.
Once they meet, it's not phalanx against phalanx, but 1 on 1 hero against hero. Il 3, 358, Il 7,252, speak of spears piercing the corselet, but the hero is able to dodge the spear, avoiding death. In the original "heroic" age it would be possible to dodge a spear piercing your oxhide shield or wolfskin, but there's no way in hell someone's going to dodge a spear which has already pierced his corselet. Note that in IL book 10, and in the Odyssey, there's no mention of breastplate and shield The "heroic age" characters didn't have them. Dolon in Il 10 had a wolfskin. I don't think that was to keep warm at night I think it was to be used as a shield, much as the Scots used their " great kilts."
Changes in customs: Gilbert Murray refers to J.A. K. Thompson from St Andrews, England, who pointed out that the "Heroic Age" combatants were headhunters.
They threaten to cut of each other's heads, ( Il 17,39, Il 17 125 ff, Il 18, 177, Il 18, 334-336, Il 22, 348)
and sometimes they actuall do so (Il 13, 202 ff, Il 10, 455-459, Il 11, 145ff )
In Il 23, 24 Achilles performed "shameful deeds" on Hector. J.A. K. Thompson figures that Achilles cut off Hector's head. The later poets edited out this crude practice, as they edited out direct references to Agamemnon's sacrifice of his daughter prior to the expedition.
And also there were significant changes in burial customs: from this online article on "Archaeology of the Iliad" CHAPTER VI - ARCHAEOLOGY OF THE "ILIAD". BURIAL AND CREMATION - Homer and His Age-Andrew Lang
"In one essential point the poet describes a custom without parallel among the discovered relics of the Mycenaean age--namely, the disposal of the bodies of the dead. They are neither buried with their arms, in stately tholos tombs nor in shaft graves, as at Mycenae: whether they be princes or simple oarsmen, they are cremated. A pyre of wood is built; on this the warrior's body is laid, the pyre is lighted, the body is reduced to ashes, the ashes are placed in a vessel or box of gold, wrapped round with precious cloths (no arms are buried, as a general rule), and a mound, howe, barrow, or tumulus is raised over all. Usually a stele or pillar crowns the edifice. This method is almost uniform, and, as far as cremation and the cairn go, is universal in the Iliad and Odyssey whenever a burial is described. Now this mode of interment must be the mode of a single age in Greek civilisation. It is confessedly not the method of the Mycenaeans of the shaft grave, or of the latter tholos or stone beehive-shaped grave; again, the Mycenaeans did not burn the dead; they buried. Once more, the Homeric method is not that of the Dipylon period (say 900-750 B.C.) represented by the tombs outside the Dipylon gate of Athens. The people of that age now buried, now burned, their dead, and did not build cairns over them. Thus the Homeric custom matches neither the shaft graves and the latter tholos graves, on the one hand, and the Dipylon custom of burning or burying, with sunk or rock-hewn graves, on the other.
The Homeric poets describe the method of their own period. They assuredly do not adhere to an older epic tradition of shaft graves or tholos graves, though these must have been described in lays of the period when such methods of disposal of the dead were in vogue. The altar above the shaft-graves in Mycenae proves the cult of ancestors in Mycenae; of this cult in the Iliad there is no trace, or only a dim trace of survival in the slaughter of animals at the funeral. The Homeric way of thinking about the state of the dead, weak, shadowy things beyond the river Oceanus, did not permit them to be worshipped as potent beings. Only in a passage, possibly interpolated, of the Odyssey, do we hear that Castor and Polydeuces, brothers of Helen, and sons of Tyndareus, through the favour of Zeus have immortality, and receive divine honours. [Footnote: Odyssey, XI. 298-304.]
The cause of the marked change from Mycenaean inhumation to Homeric cremation is matter of conjecture. It has been suggested that burning was introduced during the migrations after the Dorian invasion. Men could carry the ashes of their friends to the place where they finally settled. [Footnote: Helbig, Homerische Epos, p.83] The question may, perhaps, be elucidated by excavation, especially in Asia Minor, on the sites of the earliest Greek colonies. At Colophon are many cairns unexplored by science. Mr. Ridgeway, as is well known, attributes the introduction of cremation to a conquering northern people, the Achaeans, his "Celts." It is certain that cremation and urn burial of the ashes prevailed in Britain during the Age of Bronze, and co-existed with inhumation in the great cemetery of Hallstatt, surviving into the Age of Iron. [Footnote: Cf. Guide to Antiquities of Early Iron Age, British Museum, 1905, by Mr. Reginald A. Smith, under direction of Mr. Charles H. Read, for a brief account of Hallstatt culture.] Others suppose a change in Achaean ideas about the soul; it was no longer believed to haunt the grave and grave goods and be capable of haunting the living, but to be wholly set free by burning, and to depart for ever to the House of Hades, powerless and incapable of hauntings."
So in summing up, the original houses do not match Mycenaean houses or Classical Hellenic houses, but houses from Homer's "dark age"
Burial customs did not match Mycenean customs or Classical Hellenic customs, but customs in Homers "dark ages".
The headhunting practice did not match Mycenean practice or Hellenic practice, but a Homeric "dark ages" practice.
The characters in the Iliad use chariots in warfare. The classical Hellenes did not use chariots in warfare.
Notice that the houses, burial customs, head hunting, and use of chariots in warfare all match the customs of the urnfield people of northern Europe between 1200 and 700 BC. , not the customs of the classical Hellenes. I think Iman Wilkens was correct that the Iliad originated from a celtic story.