I think Apple just wanted their own Game of Thrones flagship, and on paper, Foundation seems like it should be that (epic scale, big ideas). But honestly, it needs a more subdued treatment: mostly talking heads in rooms, and an anthology that jumps forward decades with each episode, rotating characters as necessary.

Blockbuster narratives need heroes, which works directly at cross-purposes to the long-term systemic thinking that defines the books. There was probably never a scenario where the high price of buying the rights could match up with the size of audience for a more faithful adaptation. (And rightly or wrongly, non-book-readers seem broadly positive on the series.)