Because the alternative is Twitter.
I'm willing to look past these flaws and stick with the fediverse, but if nobody I want to follow is doing that, there's no point.
I hope Gargron et al can make it happen and beat both Threads and Twitter, but so far they've just been too stubborn (like the search and quote-tweet things) and haven't iterated fast-enough to really compete.
Free flow of information, huh?