While I don't own every single TES game, I do know the basics of all of them. And I do noticed that the lore seems to be constantly evolving.
When Arena came out, it was sort of like a fetus. It was set in a very basic and generic Tamriel that had little to no backstory that I personally know off. Then came Daggerfall, while it did developed the background and culture of Tamriel; (Though mostly just the Illiac Bay, with a lot about Cyrodiil.) Albeit it was still something of a generic medieval European theme. (I recall even Morrowind was somewhat like that at the time.)
Then Redguard came out. While from the gameplay I've seen, it didn't show much new lore (I never play the game so I am probably wrong on that.) It did came with the PGE first edition. Which described Tamriel in a much different manner than what Daggerfall and Arena described. One such example of Cyrodiil being a tropical jungle. And most of it was written by no other than MK
Morrowind then came out and even expanded on MK's version of Tamriel. (He was still a main writer after all.) mostly by updating current events as Redguard was set in the Second Area. This "era" of Tamriel's writing and lore is perhaps the most popular among Elder Scrols fans, especially the ones who played the older games.
Oblivion came out. There quite a few retcons, the biggest of which was turning tropical Cyrodiil into a Gondor 2.0. Many people were understandably pissed of at Bethesda for doing this, it didn't help much either that the game didn't even properly represented Nibenease and Colovian culture, making the Imperials look like they were one the same. (I even recalled Todd Howard admitted into getting that part wrong, but I don't know of a link.) And the politics described in the PGE were "watered down" to say the least. And it was during that time I believe that MK wasn't a lead writer anymore...
When Skyrim came out, it did acknowledged some of MK's newest work (WGC and Many Headed Talos are an example) and older ones. (Painted cows.) However, a lot of loreumnites complained of some changes. (One example of Alduin being Akotosh's son when it was explained that they were different aspects of the same soul.) Overall, some thought it was a better than what happened at Oblivion and others thought the lore was basically being "slaughtered". (Might be a bad choice of words.
Then there's ESO. While not released; there were, and still some, controversies on these forums about how much of the lore they changed. (Such as giving a different explanation of how Cyrodill got forested when MK already wrote an explanation himself, which was acknowledged by Bethesda.) Mainly though were the little things.
So the question is, do you think Bethesda or Zenimax are trying to change a lot of what MK contributed on purpose? If so; then why? Is it because they wanted to appeal to "casuals" (For lack of a better term" that wouldn't get most of MK's stuff? Or is it because they have a different group of writers that have a different vision than what MK and his crew had in mind? Do you prefer the change or you don't?