As a datapoint, my “bookmarked songs” playlist that I’ve been adding to for about 10 years is ~600 tracks, roughly 10 of which are greyed out, having been removed from Spotify.
Neil Young took all his music off Spotify because he was mad about Joe Rogan. I wouldn't be surprised if services started pulling Kanye's stuff in light of his new bit.
I just don't want my music library to be beholden to musicians or labels or tech companies trying to disassociate with the bad guy of the month. Obviously it's not a perfectly independent solution to upload to Apple's servers, but the system is working as it is.
I think the average Spotify customer might have a different listening behavior than you. From my personal experience, I have never had an album I listen to regularly be removed. I'm not saying it doesn't happen I'm just saying I bet it doesn't impact many people. And I don't know anyone who has a lot of music they listen to that's not on Spotify, if any. Again, not saying what you're saying isn't true, just that I think you're not the average Spotify customer.