OK, separate from the question of whether bombing hits max out at 10 damage for a square worth 10, let me take another shot at this math:
US builds 2 bombers and 2 rolls a turn (I wouldn’t necessarily do it this way, but it’s a good example)
Assume success in the technology at the start of US3.
Assume germany makes 40 per turn - bombing (a conservatise assumption since you are leaving germany alone)
A non-heavy bomber does 2.9 damage per shot (counting AA;'s), a heavy bomber does 5.8 damage per shot.
Bomb # hitting Germ Damage Germany Spends
Normal US0 0 0 40
Normal US1 0 0 40
Normal US2 1 2.9 37.1
HEAVY US3 2.83 16.43 23.57
HEAVY US4 4.36 25.29 14.71
HEAVY US5 5.63 32.68 7.32
HEAVY US6 6.7 38.83 1.17
So germany gets 3 full builds, and is not receiving as much pressure from the US so can afford to send the bulk of them at Russia.
I don’t know, that’s plenty of builds for me to put enough pressure on russia to allow them to be weakened when japan breaks through. and meanwhile africa is more vulnerable to conquest by germany or japan as well. I’m just not convinced that the 24 + 15 cash germany uses to turtle after its first three builds is really insufficient to defend itself. while it’s first 3 builds focused primarily on russia can get the job done in terms of exhausting her resources.
Doesn’t strike me as unbeatable at all.