@DireGoy the houthis also aren't shooting back.

Those really big bunker busters tend to be gravity bombs so they have to be dropped from above the target.

I'm sure B-2s can penetrate Iranian air defenses better than most aircraft, but I doubt they can just fly over underground facilities deep in Iran. They'll just fly as close as they can (maybe a few hundred miles away), and launch cruise missiles or ALBMs. Those have way less penetrating power.