A big deal is made of a number of British aircraft, that while designed for combat would up as trainers. The US had the luxury of not only starting later but having an industry large enough (or of being capable of expanding enough) to build thousands (if not 10s of thousands) of trainers.
Twin engine trainers include the AT-9
792 built
The AT-10
2370 built
The AT-7 Navigator
1141 built
The AT-11 Kansan
1606 built
The Cessna AT-17
several thousand, numbers get mixed with the Utilty and cargo versions.
The Fairchild AT-21
around 170
Boeing?Stearman tried for a contract
only 2 built.
That is just the twin engine trainers and does NOT include the older or obsolete bombers used as trainers. Single engine trainers are much more diverse than this and built in much greater numbers.
The British might have built a lot fewer Battles and Hampdens and Blenheims but they would have needed even more trainers than the Oxfords and Ansons they did build. Net gain in operational aircraft would be????