The Superfortress over Korea

Why did the Air Force choose to operate the B-29 over the B-50 in Korea? Was it a matter of the number of airframes available or was it because SAC needed the B-50s for the nuclear deterrence role? It's a question that's been bugging me for a while given the fact that on paper at least the B-50 was better in terms of payload and overall performance compared to the B-29.

I suspect it was a combination of the B-50 being more capable and hence more valuable for SAC, combined with the numbers of airframes available. Per Wiki there were 3970x B-29s built and only 370x B-50s.

I do not know how many B-29s were still operational during the Korean War, but since the B-29 was good enough as a bomb truck to carpet bomb troop concentrations, villages, and cities from 20,000+ ft there was really no reason to use the B-50s.

Here is the reason. Was the B-29 Superfortress a Failure?