I don't agree. There are still serious organizations and people using Twitter. I believe that to be true. I'm just surprised they haven't moved.
For example there are emergency systems or local governments that announce information on Twitter. These feel like serious organizations to me. At minimum I feel like they should be in multiple places and not just Twitter.
Ultimately Twitter is timely and has almost universal mindshare.
A few weeks ago when there was the pacific earthquake, I had family who were very close to a danger zone vacationing. Google was not sufficient for finding good local timely info as an outsider but twitter was.
I would never even think to check BlueSky or Mastodon, and my family will never have heard of them.
Things have to be posted in those other places for your regular person to have a chance of hearing about them eventually. If everyone waits for some adoption threshold to support something then it will never reach that threshold.
For example there are emergency systems or local governments that announce information on Twitter. These feel like serious organizations to me. At minimum I feel like they should be in multiple places and not just Twitter.