If this were the case then Bethesda would have destroyed Hammerfell and High Rock after Morrowind came out. The cries of "Daggerfall this" and "Daggerfall that" were as loud in 2002 as "Morrrowind this" and "Morrowind that" in 2006.
THIS GUY! ^ "Your speechcraft has increased!"
To the OP - the same thing crossed my mind when I heard about that (never read the book, though) "Morrowind is better than Oblivion!?! We'll show them! Muhahaha! BOOM! How you like your Morrowind now, biatches?"
However, I like to imagine that Bethesda has more respect for their modding community than that; even though there are some people that consistently dog every new TES game, saying the previous one was better, not everyone shares this view or hops on the "lets trash the latest TES installment" bandwagon. It's like bands - if fans liked their first album, some will always complain that the band "sold out" when they inevitably experiment with new directions. New fans that had just got into the band's latest album (whether it's the 3rd, 5th, etc.) will usually say that that album is their favorite. Most Elder Scrolls fans have a favorite game that they think is the best (though I don't think any game can be perfect to anyone). It all comes down to taste.
Ironically, some of Bethesda's biggest fans have become their biggest critics, because Beth didn't make the sequel game they wanted. In fact, to listen to some "fans", you'd think that even playing their
favorite ES game without mods would be unbearable. Fortunately, the mod-ability of the games (mainly post-Daggerfall, though modding started there) lets modders make whatever their particular vision for Tamriel is come to life. "if you don't like it, you can change it."
Anyway, even if Bethesda had intended to "kill Morrowind" as an act of revenge on what they perceived as a disgruntled and non-supportive Morrowind fan base, it would be rather pointless, since those people would just keep playing Morrowind with whatever mods they like, and just ignore the events of that book or game sequels, etc. as non-canon. It would be like I kinda ignore the latest Star Trek movie as not happening in the Kirk&Spock universe or sometimes try to forget that the Star Wars prequels ever happened.
It's your own imaginary world, kids; do whatever the hell you want with it!
Cheers.