They just closed a single API which was also abused by botfarms. Closing the API immediately improved the site from a spam perspective and was welcome by most actual users, likely all users who understood the impact.
This is pure cope - the site is doing a TON more than it used to, and more stable than ever.
Also arguing that a site that is designed to scrape and re-represent a website without ads or other stuff 'was likely a huge load' is a very weird argument to try and claim the site is no longer being used.
I can say anecdotally I used to use nitter, and while it didn't work for a few days I switched to the regular site. Now I would never go back. The actual site works better now, I have no need. On old twitter 1.0, nitter worked better.
Thats a black eye on Dorsey twitter, not the new twitter (or X or whatever you prefer)