Kinda sorta true. The plane lasted 10 years before it got replaced. The B-58 was more a victim of its time, when plane technology, or pretty much any military weapon development was very much in flux.

This was a time in which the M14 lasted only 5 years as the primary issue assault weapon before being replaced by the M16 which is still in use to this day. The B36 lasted only 12 years before the B52 replaced it. There was a lot of development and innovation during this period, probably because we were in an arms race with the Soviets, who also developed and replaced a lot of shit, too.

It's just absurd that it could never be converted to carry conventional bombs. It's only mission was to fly 1-way, low level nuclear strike. It's a gorgeous plane, for sure, and i love it, but it's close to the height of absurdity of Cold War thinking (if not quite at Valkyrie levels (the coolest plane of all time)).