Heavy tanks is not an argument you got TD's for that but they are not used because the 85 and e8 take their roles. this game is also becoming boring as fuck because of it. nearly 99% of all the soviets and ami take the e8 and 85 commanders and you use a build specifically to counter this. Other doctrine that could ad so much debt and strategy to this game are currently not viable.
No, they don't, not even close.
Thing is, its always better to have numerous medium tanks then a single heavy. The firepower of multiple tanks alone is good enough reason. Thats why T34/85 was always more popular then IS-2.
There is also the extremely dated axis players mindset that if their tank got more then 200 armor it should roflstomp everything below IS-2.
Heavy tanks are strong and potent, but they won't stop the tank force of greater fuel cost, especially if its bolstered by doctrinal abilities like mark target and this have nothing to do with T34/85 or EZ8 price, but the axis mindset that "superior kurtz steel should not need any AT support".