I'm old enough that I used Twitter before it had @-replies or hashtags built in. I spent all of 2018 in TweetJail.
I'm not sure why I'm saying all this.
I think it's because all the really good stuff in Twitter (@-replies, usable clients) was actually designed and built by users, not Twitter. Twitter, the company, didn't embrace those ideas until very late.
Mastodon and other fediverse remind me of that time, when good ideas could come from anywhere. It's the bottom-up experience that's been missing from the web for years.