They didn't take the Thompson to the 1000 yard matches at Camp Perry for ****s and giggles. That's not what it's meant for. Under 50 yards, where it had all of it's power, it had no problems with accuracy.
Yes, it was expensive. It being heavy meant the recoil wasn't as bad. The recoil was a little heavy, but manageable. That is unless you were a limp wristed European.
Very few people could get up from a .45 with a smile on their face. No one was getting up after getting clipped by several .45's or more. The same can't be said for the 7.62x25 or 9mm.
The Thompson was one of the best SMG's to cross that war. But of course, since it was American ingenuity, it sucks in your eyes. Especially since it helped to win that war.