I agree.
With those specs, I would say impossible.
It is not. Most of the R&D is already done with Altay. In fact, things will get cheaper for other projects. When you go from 68-70 tons to 50 tons tanks get a lot cheaper. For example, there is a huge price and availability difference between a tightly packaged 1500hp powerpack (engine, transmission, and cooling solution) and a 1000hp diesel generator. This is true like every single mechanical part.