I would say that reddit quality has declined a huge amount, but people won't leave because there's a huge network effect. Nobody will join a reddit clone that is 95% functionally the same because there's nobody there. Every community that tried to migrate off reddit to a reddit clone has failed.

As an example of why reddit is so bad now (aside from the obvious moderation issues) about 1-2 years ago, reddit added a block feature that stops you from replying to any comment the blocker made and even any comment somebody else made below them.

So pretending this is reddit, I could make this reply saying that you are wrong and then say you have no evidence for your claims. Then I could immediately block you, making it look like you have no response. You are also not allowed to edit any of your comments saying you got blocked or else it will shadow delete that comment.

I have personally witnessed this abuse 5 times in the past few months and I don't even use reddit that much.