That’s the thing, though. The reason they announce these projects so early is specifically to drum up fan hype (and to make the brand look appealing to shareholders). That’s why they announced Rian Johnson’s trilogy before TLJ came out, and why they announced Benioff and Weiss’s trilogy before Game of Thrones Season 8 came out (then quietly shelved it after the reaction to season 8). They were jumping the gun to make these grand statements about their future movie plans, and in the case of Benioff and Weiss, it looked they were just trying to grab onto the Game of Thrones hype train at the time, not actually considering whether those two were even the right fit for Star Wars. (Which they definitely aren’t.)
As for Rogue One, I still wonder whether the reshoots actually made the movie better or worse. With Solo, I’m almost certain they made it worse. Both films were meant to be more experimental and push out of the genre confines of what a Star Wars movie could be. But it seems Lucasfilm got cold feet and wanted to rein those projects in and make them more conventionally Star Wars. In a way, the “anthology film” concept has been repurposed into those Disney+ series, which I think is a good move. I’ll give them credit for that. That allows for more experimentation and takes away the pressure of box office performance.
Marvel does have plenty of source material, but so does Star Wars. Since Marvel seems like more of a tight ship overall, I’d say the best comparison to Star Wars would be the DC movies. DC is really in a similar predicament of just trying things out, cancelling things often, and not being sure of what direction to take going forward beyond just “People liked that character. Let’s give them more of that character.”
But, of course, the main problem here isn’t the cancellations themselves. It’s the premature announcements that are designed to drum up hype, then never go anywhere.