Those services are available, however, people would not stop using Twitter and will continue to do so until we stop consuming their content, then maybe they will finally get off Twitter...
It's companies. Corporate PR accounts never migrate off to Mastodon/Bluesky/Threads. Many neglects update of updates pages, announcing everything on Twitter.
Some of them would move to Instagram if it makes sense to do so, but Twitter apparently makes the best ad ROI figures among Twitter-like services.
I mean, lots of local and/or small services announce disruptions on Twitter only. Many of those have separate news/service status pages on WWW, and yet neglects updates of those. Possibly because users without access to Twitter aren't worth informing.
IOW, Twitter still is a social data infrastructure, like road or tap water. Something that the society depends on, that also ain't nobody paying for it, something that only makes sense at-cost max or at a loss.
I think that was always a fundamental problem with Twitter as a for-profit company. Surely it handles a large amounts of important communications, that are also not so exploitable or monetizable, ethically or not, just fundamentally.
I question your definition of 'need', mainly because my only interactions are interest-related, not work/life related, and whenever I capitulate and follow the link, it's not as interesting/useful as it was purported to be.
As such, I find it easier and easier to just not visit. This is, however, entirely my own anecdotal.
