See Joe Baugher's web page,
For an overview of what the B-29 was doing.
Then try to decide what alternatives might present themselves.
Like the B-29s were flying from Japan and from Okinawa which would a be a long mission for A-26/B-26s.
If the B-29s were scraped and not available would have B-50s been available?
Would have been B-45 Tornados been built in bigger numbers?
It does look as though the B-29s, after a number initial troubles, did manage to hit just about all major targets just before the Chinese ramped up things in Nov of 1950.?