The Sherman was a mediocre tank. From what I understood the US learned the wrong lessons from the early stages of WW II and devised the Sherman more as an infantry support vehicle while lightly armored fast tank destroyers would do the tank-on-tank battles. There were two things going for the Sherman: cheap to produce and very reliable the exact opposite of the German zoo tanks (Panther and Tigers). As the saying goes there is a quality in quantity.
I believe the Brits referred to Sherman’s as “Tommie cookers.”
The Sherman was actually a compromise between the three traditional Army branches (Infantry, Cavalry and Artillery) that satisfied nobody. The Infantry saw it as a support vehicle. They wanted thick armor, wide tracks, and a big high velocity gun that could destroy other tanks and bunkers. They didn’t really get it.
The Artillery said that since tanks had cannon on board, they were basically mobile artillery. They opposed a long high velocity gun. They wanted a big, short barreled gun that could fire 1,000 rounds without burning out. In reality almost no Shermans lasted long enough in combat to fire 1,000 rounds. They got the gun they wanted.
The Cavalry saw tanks as the heir to the horse. They wanted the tank fast (narrow tracks) to do traditional cavalry functions; exploiting breakthroughs, flanking, scouting, etc. They weren’t interested in tank on tank battles, which they said could be handled by anti-tank guns or a different heavy infantry support tank (which was never built). They mostly got what they wanted. Unfortunately for them, the Germans had other ideas about tank on tank combat, and much better tanks for that job.
The US had a flawed armor doctrine.
We maintained that AT guns and Tank Destroyers were for fighting other tanks and that tanks were for destroying infantry and breaking through. Patton supported this doctrine and wanted another coaxial MG in the Sherman’s gun mantlet.
We did, however, learn one VERY important lesson - there must be LOTS of them. Shermans were produced in prodigious quantities, were easy to transport by rail and road, and were mechanically reliable; these are the qualities that made them winners.