It may be worth remembering that the M4 was not the only American armored vehicle in the ETO: the M10 and M36 tank destroyers were also in service, the latter mounting a 90mm gun. And (if I remember correctly) the M26 used many drive train components that were identical (or similar) to those used in the Shermans…
That would be wrong. Even a glance at a Sherman and Pershing will show they are from compleltely different design schools. Too, your statement falls flat in that Shermans used several different power plants, including a radial aircraft engine mounted vertically (the basis of the high silhouette), Diesel engines and even a version using FIVE V-8 engines linked togther. This contraption was mostly given to the British as the M4A4.
The Pershing bears a strong family resemblence to all US tanks through the M-60 Patton, as even another cursory glance will show. The Pershing was deployed very late in the war and only a few were in action. Even those had problems with over-heating engines and blown cylenders. The 90MM gun was quite a good weapon though.
History shows that in a cold blooded sense, the American decision to keep the production lines humming by producing a huge number of Shermans and Sherman variants (over 64,000) was a good thing in a macro sense. The Germans funded (to use today's venacular) dozens of projects, most of which produced few useable tanks, while their troops at the front were constantly short of good operational tanks. The Sherman -was- robust and reliable, unlike the German tanks, which like German cars today, needed lots of TLC and spent lots of time in the shop in the best time. On the other hand I had a Porsche 928 some years ago, and that was the best car in the world.
Walt