My personal Musk dream is that he'll abolish that. If I never have to see tweets of pictures of text or tweets ending in `/n` again, it will be too soon.
Though, I sort of remember that Twitter was architected initially in a way that relied on the short tweets and it was a surprisingly complex change to even bump it up the little that they did recently, so who knows.
I guess bumping the limit up while keeping the ability to interact with all kinds of SMS systems and ancient phones was a challenge, or just required waiting a few years for some of the weirder systems to die out.
Interestingly when they doubled the character limit they also started double counting CJK characters so the limit is still effectively 140 for those languages.
CJK languages do tend to be relatively dense when written and counted by their code points.
I think there are some interesting observations in how both twitter and tiktok set out with short maximum lengths, establishing a culture of short, easy to digest messages, before relaxing the limit a bit. I'm not sure how much you can relax the limit before you turn the platform into something else entirely. But on the other hand there is a pattern of users circumventing the limit anyways. It will be interesting to watch how it develops over the years.
n[0] = 140
n[k] = 2/k * n[k-1]