Correction: One time. One game eschewing or going against previously-established lore is hardly a trend by which accurate anolysis can be based.
And really, Oblivion is an example of the one ignorance or retcon of previously-established lore that had the most and biggest negative reaction. Less infamous retcons have been happening all throughout the series.
Consider that, pre-Redguard, the Dwarves were not the Dwemer in all of their complexity and uniqueness, but the stereotypical bearded little men of fantasy. It wasn't until Redguard that it was retconned that the term "dwarf" is a misnomer, that Dwarves are actually as tall as everyone else, that they are actually of the same developmental line as the rest of the Mer, It wasn't until Redguard that the yawn-inspiring stereotype of the archetypal fantasy dwarf was shattered and replaced with the vast characterization of Dwemer beliefs and culture that we have and love now. In this particular instance, hooray for not giving a crap about previous lore.
Or what about the transition that took place between Daggerfall and Arena? Where the game's basic lore foundations went from a bland DnD campaign setting to a more unique and vibrant world? What about the recently-introduced concept of kalpas, potentially rendering everything we thought we knew about the dawn era and the events of creation null and void? Is it breaking with previous lore? Certainly. But it doesn't fall under the fatal lore-forum category of Boring And Therefore Wrong. And so it is accepted in a contemplative scholarly sense and discussed, rather than torn apart as contradictory to past knowledge. It's not the breaking from past lore that's the problem. It's the manner in which the replacing lore is executed, the explanations the new lore provides and how it meshes with the things it doesn't change our views of, and it's whether or not the new lore is interesting and engaging, rather than BATW.