Was only used by the USMC in small numbers at the beginning of the war and was then discarded due to crappiness.
Well it's not stated that it perforemd crappy, it was just discarded after time because they were successful in shipping robust numbers of Thoms.
Dude, did you even read the Wikipedia link you posted? It
explicitly reads that it did performed
crappy.
Sure it was accurate, light, and cheap, but parts were not interchangeable, you couldn't (dis)assemble it blindfolded (in the dark), it was difficult to maintain, 20-round magazine was the biggest available (and even that was unreliable), recoil was enough to fold the folding stock, it jammed frequently because of its design, it couldn't handle field conditions etc. which is why frontline units flat-out
refused to receive it and if they had been burdened with it, "lost" it at the first chance.