Actually German infantry weapons were the best in the business. The allies had a tremendous fear of the mg42 and tiger tanks, and even paratroopers from the 101 AB swapped their Thompsons for MP40s whenever they could Most of the allied success came from air interdiction efforts and artillery. The beat examples of these were during the battle for Normandy, where typhoon attacks shredded tank columns in the Falais Pocket and arty leveling towns such as Carentan and Caen. The battle of the bulge also highlights the p47s which completely annihilated German supply lines after the weather cleared.
Hitler was the biggest armchair general anyway and had no business running a war. He constantly ignored his smarter generals such as Kluge, and because of ordering his crappy counterattacks, such as OP Luttich, he completely shredded his panzer divisions, with the majority actually being shredded by allied aircraft.