A highly skilled but socially inept engineer is not a top performer. Interacting with others is part of their performance. Ultimately you need to look at the sum total of time, money, and outcome for the entire team; if firing a single "rockstar but asshole" developer allows the rest of your team to achieve the same productivity, you're still better off because you're saving both money and time on that person. Conversely if a single such developer can replace your entire team… sure, go for it.

In the extreme, if bcachefs gets removed from the kernel, the productivity outcome (depending on your measure) is actually zero.

[Ed.: also, honestly, if you need to hire a "babysitter" for such a highly skilled engineer, that is also a viable option & there shouldn't be a social stigma for that either. I wouldn't say it's the manager's job though, not to that degree at least.]