impossible scenario

You can say it a thousand times, but the fact that you complain about constantly running out of ammo means that, yes, you ARE wasting ammo. Now, I don't know exactly what it is you're doing wrong that's causing this problem for you, but I do know you're doing it.

OK, but again, by definition, you're wasting ammo. Why? Because you have the option to not use any at all, and you're choosing not to take that option. Fine, you like to play that way. That's cool. But don't pretend like you're not using ammo that could have been conserved for hairy situations like, say, boss battles?

Well, that's good.

No, we completely understand: you're chewing through ammo like it's going out of style, and have thereby screwed yourself. What you seem to refuse to get is that you shouldn't need to do that.