To reverse the question, take armour. The American’s ‘best’ tank was the Sherman, which was outclassed, but performed for the allies. Had, say, the Pershing or Centurion been available in 1943, maybe we’d be asking how they’d have coped without them.

Regards

Or the British Comet tank in mid-1942?
Thus in time for initial combat deployment in North Africa with Operation Torch?