They can't really remake Morrowind because they'd be competing against Skywind. Bethesda are a generic evil company but they're aware of their perceived good relationship with modders, and they're keenly aware that sending a cease and desist to the Skywind team to clear the way for their own inferior remake would make everyone utterly despise them. I think there's a similar Oblivion remake underway.
They've sort of locked themselves out of re-releasing Skyrim again because it's become a meme at this point. After resting on their rapidly-declining laurels, the only way for them to go now is forward. I wouldn't be surprised if they haven't got a clue what to do for TES VI and Fallout 5 at this point, though, and they're just trying to keep the hype machine going to keep people's interest up despite the fact it's now been over a decade since their last unambiguously well-received release, and that Fallout is more or less a dead franchise now thanks to them shitting out two big soulless failures.
It's so strange to think that they had such a good run from Morrowind through to Skyrim - Morrowind 2002, Oblivion 2006, Fallout 3 2008, published New Vegas 2010, Skyrim 2011. A new critically acclaimed (by the mainstream, at least) blockbuster every couple years. Contrast that with the last decade - only two releases, Fo4 and Fo76, and they're both unanimously considered to be total shit. Looks like they've got another boring waste of time on the way with Shitfield. What the hell went wrong for them?