zarkov,
The problem is that every scenario that comes up in which any model of Brewster Buffalo was used the guys running it are putting the B-239 in. Midway, early CBI, Dutch in Indonesia. All of them. The lack of the appropriate model of Brewster doesn't even slow them down.
Yes, we need the Ki-43-I, Ki-43-II and Ki-43-III, but if the only Buffalo we have after getting the Ki-43 is the B-239 then all that means is instead of A6M2s vs B-239s we're going to get Ki-43-Is vs B-239s.