This is true, but the way you wrote it ignores the fundamental problem - it's not we can't make transistors switch any quicker, it's that doing so causes such an increase in temperature that we risk damaging the device. That's why you can read about overclockers using things like liquid nitrogen to run chips at 8 GHz.
Cooling mechanisms like microchannel cold plates and, as we continue with 3D-ICs, interlayer cooling, can allow for higher frequencies.
I don't think better heat extraction would really change that much for today's CPUs (certainly when we head towards 3D chips it will become critical).
Gate delays are smaller at low temperatures; those LN2 overclocking runs aren't just fast because of efficient heat dissipation from the CPU, they're fast because the chip is being actively cooled to below room temperature.
So while heat dissipation is a factor, we're also close to the electrical limits as well. Otherwise water cooling (replacing the stock heat spreader) would get closer to LN2 runs. ALUs run at higher frequencies than the rest of the chip, but they're designed to do so (you'd have to shorten the gate pathways like a P4 to do that to the entire chip).
But ultimately, performance per watt is almost universally optimised for these days. It's critical in servers, laptops, mobile phones - The demand for 6ghz, 300W CPUs would be limited to workstation chips, even though we could probably engineer them to be reliable.
Power consumption is always going to increase super linearly with respect to frequency, probably as a fundamental property of any method of computation we use.
This is true, but the way you wrote it ignores the fundamental problem - it's not we can't make transistors switch any quicker, it's that doing so causes such an increase in temperature that we risk damaging the device. That's why you can read about overclockers using things like liquid nitrogen to run chips at 8 GHz.
Cooling mechanisms like microchannel cold plates and, as we continue with 3D-ICs, interlayer cooling, can allow for higher frequencies.