Were American tanks during World War 2 lacking in sufficiency?

Ah, my favorite topic. That of /u/the_howling_cow , as well, see his monster post over here. https://www.reddit.com/r/AskHistorians/comments/6ilw88/comment/dj779ud?st=J47J4OXE&sh=5883263b

If you wish to rate the Sherman as compared to a famous German tank, facing off, one on one, at about, oh, 1,500m on a beach, then, yes, Sherman lacked in sufficiency. If you wish to rate it on any other measure, to include, oh, being a war-winning system, then absolutely not.

Unfortunately amateurs who compare tanks look at basically two important factors, sometimes a third. Gun penetration. Armor thickness. And maybe burst speed. The tank with the biggest numbers is the 'best'. In such a case, that means that the poor old Sherman is struggling against a Panther. However, such a basic comparison absolutely beleaguers everything else which is important in a tank, from "how quickly you can shoot at something" to "can you rely on it to be where you need it to be when you need it to be there". All of which are categories which the Sherman has in spades. Almost nothing left the shores of the US unless it was utterly reliable and sustainable. The Germans...well... not so much.

True, the light tanks were a little outclassed by 1944, the arrival of Chaffee was long overdue. And a significant error was made with Sherman in not developing appropriate ammunition (High Velocity Armor Piercing) for the 76mm until after it was needed. That said, there may well have been other calls upon the tungsten supply which at the time seemed to have been (and may well have actually been) more important, though I don't know if that was true or not.

The bottom line, before I would direct you to my 'Inside the Chieftains Hatch' tours of Sherman and Panther, or my "Myths of American Armor" video, all on YouTube, is that Shermans were a vital part of the side which won the war. You can't really argue with success.