  We demonstrate a spontaneous tendency of quantum wave packets to become
quasi-classical, providing a classical limit for the Universe dynamics.
However, this limit is not maintained in the future (after a critical value of
the relational time) and a spreading process is turned on. We show that the
onset of an inflationary scenario is not able to make this localization stable
of the wave packets for the Bianchi I model. Instead, when we implement a
perturbative inflationary scenario for the isotropic Universe a mechanism of
stable classicalization of the Universe emerges. This result outlines a sharp
difference between the standard relativistic cosmology and a modified $f(R)$
paradigm.
