I wouldn't blame Patton as much as the devleopment guys for being too slow to get things approved and moving forward. If they'd done things with more urgency the Pershing may have been in combat by the fall of '44 in time for the Battle of the Bulge.

76mm Shermans were available in April '44 though none landed on D-Day. It wasn't until they clashed with Tigers and Panthers en mass that they began to clamor for them in July '44. Funny, the guys in Italy knew all about the advantages of the 76mm Sherman and were using them already. NIH (Not Invented Here) syndrome?

We hear a lot about the failure of the TD concept and in Zaloga's book his opinion of the M18 was that it was a failure of a design. However, the M18 knocked out far more German armor then they gave and the crews loved them. The TDs had the advantage over the sherman of superior situational awareness, the ability to react to threats much faster then a crew viewing the war through periscopes. Of course they were more vulnerable to enemy fire of all types. I wonder what their loss rates were? Haven't been able to find that.