My Dad was a junior officer in the 45th ID (Thunderbirds) in the SLOG up Italy and at Anzio. The disaster of the Anzio landing was the pause to consolidate, reinforce and organize without pushing out to the surrounding high ground. US Generals John Lucas and his immediate superior, Mark Clark, have been strongly criticized for allowing German forces to close the beachhead and turn a brilliant around-the-back amphibious attack into a 4+ month siege and bleeding! Somehow I cannot see General Patton making the same ‘caution’ error and PERHAPS done better at the battle up from Salerno!
Anzio showed how quickly German forces could regroup and react to dynamic conditions. The British had remarked about the speed with which the Germans could recover from a defeat. Anzio had taken the Germans by surprise, but the Italian campaign only had one real object, which was gaining control of 13 airfields that lay within striking distance of the Romanian oilfields and some industrial areas — after those objectives were taken, there was no further point in advancing up Italy, part of Churchill’s “soft underbelly” delusion.
Interestingly, Hitler shifted several divisions out of the preparations for Zitadelle, and into Italy, where they were probably not needed (the terrain made for some of if not the toughest fighting in the European theater), and perhaps costing victory in the Battle of Kursk Salient.
This isn’t surprising, considering Hitler was almost as bad as Churchill and Stalin at the tactical level — always the wrong move it seems. Even his rabbit out of the hat — the Battle of the Bulge, which aimed to destroy the Allied hold on Antwerp and starve them of supplies — wound up leading to a general German collapse, even though superficially it delayed the seeming end of the war.