Mastodon grew, but only took a tiny slice of Twitter
Growth is not the only, nor even main, metric to measure success of fedi. Fedi is not a VC-funded startup that needs to grow exponentially to remain viable (consider how that worked for Twitter and Reddit…).
Building a resilient, safe, longterm-viable communities is the metric to measure fedi by. That takes more time, than hooking people on endorphin/noradrenalin high and slick interfaces.
half of Mastodon are bots or people who crosspost to both.
This is false. I follow a couple of thousand people and have an interesting, diverse, funny, and informative timeline. Very few accounts I follow crosspost.
There is no recommendation algorithm so your timeline is what you make of it. It takes a bit more time to curate, but you end up with your own thing that suits you — if you put in the tiny bit of effort required.