I thought it was the combo of the turret rings on the Allies tank were too small to be upgunned (with the 76mm & 17prd exceptions ) & most German tanks in the ETO (European theatre of operations) were taken out by anti-tank guns,but the Allies tanks during WWII were “questionable”.With the allies it was a numbers game,the Germans built a small number of good tanks,I think they worked on (I think) 6-4 Shermans per Tiger (pity being in the first Shermans!)
RE the Russians,the Panther was a German take on the T34!Plus the engineering went the other way,I think the AK47 was influenced by the MP44 & the RPG (rocket propelled Grenade) was influenced by the German Panzerfaust & US bazooka.
But I stand to be corrected.