I don't see why it can't be both. I've also heard this from the better-compensated police. Not discussing "physical danger" or whatever mind you, but the toll of constantly facing conflict and seeing some of the worst of humanity. Not a direct parallel, but burn out extends beyond compensation. I've also heard this from social workers, who granted also deserve better compensation.

I think it's possible we should be spreading out emergency response better amongst society, but I don't have much in the way of practical suggestion.

Of course, we should also compensate our non-police emergency responders much better. My understanding is that EMTs make close to minimum wage and tend to carry higher individual liability.