I made no comment on whether such things 'happen all the time' or not. They probably do (and remain potentially dangerous for the careers of people who do).

My point is that saying they're dangerous (and we shouldn't do them) is not really helpful, since humans being humans we'll likely still do it. Instead, I'd like to think of ways to reduce the harm and make the dynamics less problematic.

Like, in theory coworkers should never date but in practice that's impossible to enforce. So many companies instead enforce a ban on relationships down the chain of command, which is both workable and addresses the biggest power dynamic.