Tank destroyer battalions had the job of killing tanks. These TDs were fast, lightly armored, packed large caliber, high velocity guns to engage the enemy tanks. The TDs were in their element when in ambush positions that allowed them to shoot and scoot. However, in a head-to-head fight, their thin armor put them at huge risk.
As things turned out, the Army's two tier doctrine did not work. Tanks were used more and more for tank vs. tank fights along with infantry support. Because they “looked” like tanks, Army commanders used TDs as if they were tanks. The TDs with their thin armor were not suited to the task and the TDs got killed in tank vs. TD fights. Post-war, the Army discarded the tank destroyer concept and the tank was to provide infantry support as well as doing tank vs. tank fighting.
Your post is a succinct and well written summary of US tank strategy and findings during WWII. Everything worked fine when used as defined. TDs killed a lot of German tanks. The problem was that war was messy. You can’t always deploy the right tool out of your Swiss army knife, even when given the vast resources of the US Army.
The Germans also had a tank destroyer problem. Whereas, US tank destroyers “looked like tanks” as you say, they had a turret and mounted the latest AT gun but with open tops and light armor, the Germans went a different route. The Germans found all those big and expensive tanks they made, the ones the movies love, well, big and expensive. To bump up production in an attempt to match the allies, and try and give everyone an armored vehicle that needed one, they took tank chassis and built up the armor sides and plopped in a gun on a pintle mount. This resembles what the Confederates did with their ironclads in the US Civil War, vs. the turreted monitors of the north.
They did away with expensive turrets and turning gear, making the vehicles cheaper. They turned out tons of open-topped and closed variants, some for infantry support, others for anti-tank use. What they weren’t supposed to be were tanks, i.e. blitzkrieg inducing offensive gear meant to tear up an enemy’s flank.
Just like the Americans, the German crews used anything with a gun as a tank, and found that the limited gun traverse and tactical vulnerability caused problems. Just as an example, the Hetzer, a reasonably useful vehicle cobbled up from an obsolete Czech tank chassis had three of the four crew sitting in line behind each other, for a very cramped and poor communication situation.
Both the Germans and Russians played with the TD concept a bit after the war, but for the most part came to the same main battle tank conclusion as the Americans.
Thank you MasterGunner. Excellent post, and much appreciated!