The biggest downfall of the B-58 was that it was a one trick pony. It was designed around the weapons pod, making it highly inflexible and not able to deliver other loadouts. I could not see the B-58 being able to handle standoff weapons, either nuclear or conventional. No internal stowage due to being designed around a weapons pod, and no accommodation for external pylons. Its Soviet equivalent, the Tu-22 Blinder, did not have such a limitation.
That was the plan back then. . .all jet bombers were designed to be primarily nuclear delivery platforms.
At the start of the Vietnam War, we really didn’t have our jets kitted out for conventional wars, from B-52’s to 105’s, they all had to be updated to perform conventional (non-nuclear) missions.
Sorry about the image size, but it would be a sin to reduce such magnificence.