This doesn't look obvious to me. You get more vacuum to play with; the probability per unit volume should remain constant.

I was assuming that there has to be stuff in space for stuff to happen. I guess I was wrong.

Do you know we aren't? :)

There's a chance that our experiences are just random, which we can't do much to reduce. All we can do is look at the probability of physics working a certain way given that we are not random. That cosmology would be ridiculously unlikely given that we are not random, because that would require that we not be Boltzmann brains, which is extraordinarily unlikely.