Because once these centralized services reach the point of defacto, they always just trying to push more and more of what they want. We're practically hitting a bubble at the moment of every social platform that took over trying to nickle and dime. It's the reason for all of this in the first place.

Facebook - Well it was always crap.

Reddit - killed all the forums, now trying to own all the text as content, making lives harder for it's moderators, and continuing not to pay them for the clearly thankless job. Quality of posts has degraded.

twitter - messed up the entire purpose of their checkbox, keeps trying to find various ways to make money, entire quality of platform quickly degrading due to server migration

Youtube - Has started pushing for more ads, and punishing users who don't watch said ads.

People think about the short-term too easily, and then just kick and scream when it's already too late, and moving requires a ton of coordinated work, and "putting up with", making new things work, because everyone let the last thing get screwed over.

The constant cycle of letting products get ruined and moving on gets annoying after awhile.

It's too easy to say "why not?" and very difficult to word "Because it always ends the same"