1- Podcat said the tanks had strategical flaws
2- I doubt it as they did have qualities (armor, gun) and the diferences between the cheaper older models wouldn´t be big enough to make building them in big numbers strategically relevant. It´s about the SUM of parts overall isn´t it? Your tank uses more fuel? Well, it´s not like Panzers don´t use fuel, and what if the OTHER qualities compensate that? Would the sum of parts still indicate that it´s better to build more of the cheaper model? If someone can prove that, ok, excellent. But I´m still waiting for that post.
"oh but Panthers had bad mechanic, etc etc" which new weapon didn´t have problems? Does that mean you should never move forward and instead let enemies get the edge? Mass production of old weapons was proven many times during the war to be rubbish (again, Zero and BF 109). Why with tanks would be different? Considering Germany was so squeezed, instead of criticizing the tank, it should be praised for even accomplishing to build a new tank in such numbers in the first place...
You still don't get it?
By having one (not 3, just 1) type of tank in a single niche you achieve several strategic advantages:
1. More ability to mass produce as factories use the same parts and same methods.
2. A synergy effect allwing to further increase numbers by concentrating technological resources on just one design to make more of them and make them better.
3. Simplified repair on the front all spare parts are widely available and any repair workshop has people trained in repairing this type.
These are strategic advantages, that allowed the Americans and Soviets to produce lots of tanks, keep lots of tanks operational and make up for any nominal disadvantages. For all the german sob stories about not having enough tanks, the German strategic choice of going for so many different designs is the key factor.
The Germans in their quest for a "superior" tank, created something that had huge strategic flaws, and the minimal "advantages" did no remotely compensate for them. Is a gun capable of hitting a target 2000m away much of an advantage, if the typical engagement range (and actual hits) is 700m? Is it that much of an advantage to have strong front plate, if your turret and hull side can be pierced by virtually any gun?
The US had the M26, the Soviets had the T-44. Both vastly superior to M4 and T-34 respectively. And both were in only limited production until the end of the war, because the americans and soviets realised the complications that would arise from trying to rush a new tank in production during the war. Had they tried it, these tanks would have probably been as crap as the Panther in 1943.