IIRC there were Boba Fett origin stories long before Attack of the Clones came out, and they were thrown out in favor of the movie.
I know people are pissed cause like Thrawn isn't a thing now and neither are all the other stupid little emperor clone plots and such, but come on those were never going to be movies anyways.
But like when it comes to KOTOR and the like, unless Disney decides to do something that contradicts it (which doesn't seem likely in the forseeable future) who the fuck cares if they say it's canon or not?
Thrawn exists, but it's different. ---
'It's okay that those gangbangers stole all my personal belongings and cash at gunpoint, cuz they're building a rec center!' - OneTimeBen