The Brit’s upgunned their Sherman successfully about mid-war. (For the Brit, Canadian, and Commonwealth forces) We could have, but Washington generals wanted the open-turret “tank destroyer” instead. But that open top left them defenseless in a town or against cannon bombardment, mortar round, elevated machine gun defenses, etc.
Tank destroyers rarely worked as theory held in the confusion of battle. GREAT in theory and mockup battles however.
The Sherman with the 17 pounder was called a Firefly and was better than our 76mm models.
Tank destroyers were preferred because they mounted the better guns earlier than the Shermans. They were also easier to escape from and had great visibility.
The 76mm gunned Shermans fought in Korea and bested the T34’s.