What if the American military in the time of Ronald Reagan fully made all of its nuclear bombers stealth aircraft like B-2s. How much difference would this make in their survivability in a nuclear exchange with the Soviet Union?
Unlikely to happen, B-2 only flew in 1989 after Reagan was out of office, tech was not quite there yet. That was actually the plan before Reagan, Carter cancelled B-1 and authorized the B-2 that would replace the B-52 eventually, then Reagan restarted the B-1 program to fulfill a campaign promise. Admittedly the B-1B had reduced RCS, but it was not fully stealth
To fully replace the B-52 by Jan-89 one would have to start procurement early, so such a bomber would be fairly primitive vis a vis the B-2 and much easier to detect, plus one would have to do mass procurement so it cannot be a secret
What would really make a difference in survivability would be accelerating the AGM-129 and developing a variant of the AGM-86 that could fit in a B-1 bomb bay, allowing the B-52 greater standoff range, and giving the B-1 some standoff range