Also in 2v2 RR it is possible to get a great comeback.
I mean the US Forces got a worst late game for real, but many players also underestimate it.
The thing is, that US got no heavies, but several hardcounters as tanks.
I always recommend to get a M36 around minute 10 to 12, even if you havent spotted an enemy tank. So you can avoid to be steamrolled if you got no zookas or teched up the Lui.
To get a comeback as USF you have to play a real good combined forces gameplay with your vetted rifles (try to keep them alive the whole game), Tanks (Shermans to fight back the inf and jacksons as support behind the line), MGs (to delay the axis vet inf.), arty (to keep the axis struggling at the trucks, etc), etc
If, like some players do, you just relay onto Rifles and tanks, you are pretty much fucked the longer the match remains.
