I hate modern Disney.
I think Disney knows. As a child I got excited by the castle opening of their movies. Classic Disney was great. If Disney was still held in such regard, it would have been proud to start TFA and TLJ with its Disney castle in lieu of the necessarily omitted Fox fanfare.
Disney often makes movies that they don’t use the Disney logo for. They didn’t even use it for Who Framed Roger Rabbit? but used their Touchstone Pictures brand instead.
But if there were warm fuzzy feelings about Disney, using their logo to replace the Fox fanfare would have been perfect.
I don’t think the Disney logo sets the right mood for Star Wars.
For me, the Fox logo and fanfare are a part of the films and the Disney logo and music just doesn’t have that feel. It’s great for Peter Pan and Sleeping Beauty, but wouldn’t work for Star Wars.