I don't think that this is what the parent says. The parent doesn't complain about the devs moving to Anthropic (presumably to work on something they find exciting and get a good salary for it).

The parent complains about Anthropic hiring devs working on interesting projects, just because they have enough money for that.

> You can’t annihilate a project by hiring its devs away.

I also disagree with that: the codebase is still out there, but what is "a project"? Many (most?) open source projects stop evolving when their devs go away.