Gear,
The only reason the M-26 was employed in small numbers was because Patton fought so damn hard to keep the Sherman production up and the Pershing production down. His (Patton's) theory was that American armour should be fast and manueverable, and that tanks should not fight tanks, just exploit break throughs. It was this "doctrine" that held up the Pershing's production when it could have been available in large numbers to combat the far superior German tanks.
Some in the army felt that Patton should have been held accountable for the deaths of so many of his tankers owing to his flawed doctrine. His death at the end of the war stopped any further action against him, and a legend was allowed to form, while in reality, many who served under him hated him for the pompous, arrogant, egotistical arse he was.