And I also feel that, like you were talking about with Claremont's stories that were Days of Future Past and God Loves, Man Kills, the 80s saw human/mutant relations move more to the forefront, but even with all the bad things that happened at that time, there still seemed to be hope and characters didn't seemed to be shamed for having hope in the first place.
The 90s are definitely the era when the antagonism towards mutants really started ramping up, probably starting with X-Tinction Agenda in 1990 and snowballing into the early 2000s with other unfortunate events such as Operation: Zero Tolerance and the Genosha genocide in 2001, as well as extremist religious cults. If it didn't seem impossible already, then depowering most of the mutants in House of M in 2005 surely made it seem as such for many, and left this sort of feeling of the X-Men limping with many wounds ever since, until recently that is.
If Xavier's dream started to feel pointless and foolish to some because of the feeling that humanity is incapable of getting better, impossible to reason with, and is irredeemable, then I myself feel there's a responsibility to be had with the writers that, consciously or not, wrote stories that increased humans' hostility towards mutants, but failed to update Xavier's dream accordingly in response. Hickman seemed to take a step back and realize just how bad the hostility against the mutants had gotten, so on his part, a big reason he probably wrote House/Powers was with an intention of updating Xavier's dream in a way that it accordingly addresses the increased hostility that had come before, and that it's not impossible for groups of mutants and humans to live peacefully on the same planet, even if they're far apart from each other.