What can be done by raising the power consumption per core to hundreds of watt, while cooling the package with liquid nitrogen, is completely irrelevant for what can be done with a CPU that must operate reliably for years and at an acceptable cost for the energy consumption.
For the latter case, 6 GHz has been barely reached, in CPUs that cannot be produced in large quantities and whose reliability is dubious.
What can be done by raising the power consumption per core to hundreds of watt, while cooling the package with liquid nitrogen, is completely irrelevant for what can be done with a CPU that must operate reliably for years and at an acceptable cost for the energy consumption.
For the latter case, 6 GHz has been barely reached, in CPUs that cannot be produced in large quantities and whose reliability is dubious.