If the absence of intermediate fossil forms holds as much today as it did back then, why should anyone accept evolution?
Darwin did not claim that the fossil record is sufficient to "prove evolution," and contemporary scientists do not claim this either. Instead, they claim that it is not a hard problem to address a failure to locate an anticipated confirmation in the fossil record, or in other words, absence of evidence is not evidence of absence.*
To address "Why then is not every geological formation and every stratum full of such intermediate links?", Darwin argued that "The explanation lies, as I believe, in the extreme imperfection of the geological record (p. 280 [Origin of Species])". (S.J. Gould, "The Structure of Evolutionary Theory" (2002), see Ch. 12)
Acknowledging this imperfection is not to say that the geological record gives contrary information to Darwin's proposal: instead, we find that the geological record doesn't give that much information one way or the other. Darwin, and scientists today, are confident that there is nothing in the geological record that is particularly contradictory to Darwin's proposal. So they look for confirmation for the theory elsewhere.
As a side note, Stephen Jay Gould popularized the notion of "punctuated equilibrium." Gould implies that this feature of evolution's history was anticipated by Darwin, when he addressed (in his time) the "harder problem" of "the evidence for global episodes of apparently sudden mass extinction or origin of entire faunas". (S.J. Gould, "The Structure of Evolutionary Theory" (2002), see Ch. 12)
*As an example of this kind of claim, consider "The Fossil Record of Birds" by Storrs L. Olson (below). The author acknowledges various weaknesses with regard to the fossil record, but does not allow this to become a sentence formed against the evolutionary model of life's succession.
...I have attempted to relate what I believe paleontology currently tells us about the first appearance and evolution of the major taxa of birds. Not all families receive equal attention, particularly those for which extensive revisions are necessary before any sense can be made of their fossil record. The need for such revisionary work continues to be very great, as I hope will be evident.
Unfortunately, the study of fossil birds has been, and continues to be, plagued by a good deal of what can only be called poor science. The idea that every scrap of fossil bird is a priceless gift to be treasured with veneration and treated as if diagnostic has infected avian paleontology down to the present.
The Fossil Record of Birds by Storrs L. Olson (1985), p. 81-82