But WWII was an offensive war - he who moves forward wins.
Yes, the Germans had the best machinegun, but that is mostly a defensive weapon - the Americans had the Garand - an extremely versatile rifle, the Thomson - best SMG in the war combined with the very light and accurate carbine and troops could move
forward and around Mg42 nests, and of course the BAR which was a great rifle for the troops that could handle it and use it as accurate supression weapon.
(6) Tommy gun had effective range of 50yrds. Most combat engagements take place at 300yrds or less.
It was meant to be used by agressive and fast runners. Sort of a quarterback weapon. While the riflemen are fighting at 300yards, the agile submachinegunner had to be running forward and around the enemy to get in range and either distract them for the riflemen to finish the job, or hose them down themselves with .45
US tactics were not based around the light machinegun, like the germans did. That is a defensive tactic. US tactics were based around the rifleman - and they had the best rifle.
The BAR was a fine weapon, but not all G.I's were 6 foot tall with the stamina of a bull. Maybe it should have been issued as a standard weapon for the Aussies though

The G.I's had some crappy tanks, but on a small arms level, they had the best equipment for fighting a mobile war.
Sorry pal but there is no arguing that another rifle should have replaced the Garand. It was the perfect rifle for the job and I have not read or heard a US veteran say he would have liked to switch his for anything, except maybe a thomson which was seen as a bad-mother****er gun, but that weapon required a certain breed of maniac to use properly, people who were able to run forward in spite of apparent certain death. Unlike the ETO, were Thomsons were given to officers and people of rank, in the PTO you had to earn it with some crazy deeds in the field. G.I's in the Pacific say they never asked soldiers how they got their Thomson.