The phenomenon that youre describing is exactly true, and was a huge problem for the German Army! There are a couple of reasons why the Germans had so many tank designs. The first was the rapid pace of technological change before and during the war. The technology of armored warfare changed significantly as guns became larger, and tanks became heavier. By rapidly innovating and updating their designs, the Germans were able to fix the defects of their older designs, and keep those platforms generally in service. Another issue was the Allied bombing effort. While it didnt really prevent tank production, bomber attacks against German factories, and especially ball-bearing factories, really affected how Germany designed her tanks. Turrets, which relied on many ball bearings, were sometimes replaced with turretless tank destroyer-style vehicles. But probably the biggest reason for Germany's constant redesigning, especially later in the war, was their obvious numerical inadequacy. Germany produced perhaps 25% of the tanks that either the Soviets or the American produced, and much less than the combined output of tanks of all their enemies. Germany was so out produced that they really couldnt make up that difference in a reasonable period of time, especially considering the allied bomber campaign. So, rather than make an inferior number of inferior tanks, the Germans opted to make an inferior number of very powerful tanks. Tanks like the Tiger and King Tiger were designed to be so power and so indestructible that they could kill several enemies before being knocked out themselves. But this plan never really worked well, the designs used more materials, took more time, and never really achieved enough success to justify their expense. In addition, the constant innovation and redesign gave the German tanks a lot of teething problems. Each new variant or design would inevitably have an issue with this or that system, minor problems which could be easily fixed later production models. The Allies had these issues as well, but where as they stuck with more tested designs, the Germans were always changing their tanks, and encountering these minor issues. Issues that, when added together, sometimes made their tanks complete battlefield flops before their kinks were worked out.