It never worked like this, though. You could always view a single linked tweet/thread; it was if you tried to view a timeline that you ran into difficulties.
That's little consolation now that he's, apparently, put it back (possibly 'worse' than before).
I am not a prolific twitter user. I am one of the "anonymous lurkers" I mentioned in my original comment. But your observation makes sense, as I only started visiting Twitter after Elon's takeover. The removal of the login wall must have been the reason.
Yep it used to be you could view individual tweets but nothing else. Elon came in removed it and made everything free to view. A couple months ago I noticed they went back to the old system. And now you can't even view individual tweets. Embedded tweets still work I guess
I think there must have been some kind of nuance beyond that, at some point. The number of people claiming that they couldn't view twitter links — and I'm sure this started pre-Elon — suggests to me that, like someone else has mentioned, there might have been different behaviour for 'anonymous' vs. 'not-logged-in' viewers.
The main difference to me was that I could see the "trending" tweets and additional "recommended" tweets after the comments on the one that I was reading. That started post Elon. There was also the login popup that was trivial to X out that seemed to appear more frequently after Elon took over.
The pre-Musk behaviour was fairly straightforward to my recollection: All logged out accounts could view a single tweet and some percentage of the replies. They could also view a profile but, similarly, scrolling down a certain number of tweets triggered the modal.