Why were Allied tanks so crap in World War 2?

No way, that would make no sense at all…

Going back to an earlier part of the conversation, I’ll chime in and note that if you had a truly hideous fuel situation coming ahead, producing a small quantity of high-quality tanks might NOT be the wrong solution.
That being said, producing fuel-hungry juggernauts rather than lightweight models closer to the Patton would be a questionable decision.