What you are saying is PRECISELY why Moore Law ended with 7nm.

Mind you, performance improvements didn't ended, we can still find other ways to do things...

But 7nm is the smallest physically possible transistor (well, theoretically it is 5nm, but that one can't be actually manufactured).

So, you hit 5nm, then what? Your only choice would be make chips larger... but if you do that, you limit your maximum clock (example: a 5cm processor, if it allowed data to travel at light speed, and had perfect cooling, would still be limited to 6ghz)

Or make them taller, but then you can't cool them easily.

That is the problem, Moore Law, as in transistors per chip, ended with 7nm, there is nowhere to go after that, the only thing you can do is add more chips and make them communicate with each other (ie: multi-cpu... see what AMD has been doing in their recent research, trying to figure how to make an API to allow infinite amount of GPUs in the same calculation in a way 100% transparent to the developer).

But making more chips is not improving Moore's Law.

The only thing that can be done now, is invent something else, silicon transistors are done for, you can't improve them much anymore, you can only change the tech (use something else other than silicon transistors) or find novel ways to use current silicon tech (better architectures, multi-chip systems, better code, etc...)