Don't we? That is pretty close to the number of firefighters in the US, and they rarely fight fires

From some quick googling, I think the average firefighter fights about two fires per month, which is pretty good! And the average specialized wildlands kind of firefighter fights fires much more often.

But firefighters don't just fight fires, they mostly do medical emergencies, which keep them very busy. And that's the problem with standing armies: we generally don't want soldiers doing a bunch of other kinds of work besides wars because they're around.