This is what I think happened:
- few companies are willing to go through paperwork to sponsor visas. Old Twitter was, Musk Twitter probably isn't
- Musk inherited a bunch of visa-sponsored devs from old Twitter, and they will have trouble finding a new h1b sponsor to transfer
- those are the devs that cannot negotiate better salaries or leave easily
Basically Musk's Twitter's lights are on thanks to those employees. And whether they are good or not doesn't matter, they can't leave either way, job market is hostile