It does make me wonder how much the ratio of forced labor H1B situations has gone up at Twitter as US citizens all bail from the fire.
I cannot imagine why anyone would work there if they had a choice at this point.
There are about 550 full-time engineers at Twitter. [1]
There are about 625-670 H1-B holders working at Twitter.[2]
This isn't quite the full story since of course H1-B holders might be doing other jobs than engineering; many of those 550 engineers are not US-based; there are other visas for foreign workers in the USA than the H1-B; and Musk has reassigned some workers from his other companies to work at Twitter.
But it sure looks like the answer is: a lot!
[1] https://www.cnbc.com/2023/01/20/twitter-is-down-to-fewer-tha...
[2] https://www.forbes.com/sites/stuartanderson/2022/11/04/twitt...
After getting rid of 80% of employees, that number has surely dropped.