Well, if the B-1 had been designed for conventional payloads or hadn't become such a political promise in the 1980 election, the B-52 would probably have been retired. Even the B-3 specs don't look like something that will retire the B-52.

Honestly, I'm really not sure that the whole justification on "strategic" vs "tactical" bombing that spawned a separate Air Force was such a good idea given the types of wars fought in the nuclear age.