You touch on a good point. The irony here is that "cancel culture" only works because labor's power is poor.

If it is expensive (e.g Joe Rogan - Spotify deal) or difficult (e.g Steven Pinker - tenured) to fire people it seems much more difficult to cancel someone.

I think that's obvious: because such outrage is infectious and is liable to spread from employee to employer.

Except that the general public seems to care much less about the outrage than these businesses do. They're behaving like socially insecure teenagers, trying to prove to the bullies that they're cool. My theory is that it's an extension of the problems of online advertising--companies know there's a lot of money at stake, but still aren't good at measuring it.