Considering the training time delays for converting -17 & -24 crews to the -29, that is exactly the decision one would expect from someone who knows the A-bomb will preempt everything.
I don’t think retraining ground and air crew for the B29 would have been that difficult. These were veterans who knew their business. And LeMay has already worked out the kinks in getting peak efficiency in flying them in combat.
At this time, there are four B29 plants in more or less full production, collectively turning out about 300 planes per month. I went to law school because I’m bad at math, but matching the existing fleet with new production I could see fleets of 1000 bombers flying from both Okinawa and the Marianas by the end of the year.
As it was, over 3200 B29s were actually produced, and in September the government cancelled orders for an additional 5000 of them.