Can't say that I agree with this.
There was a leak at Computex that showed a 3950X at 4.25GHz all core, each core consuming 5.5w at 100% load. Sure, there's power required for the IF and IO die, but it certainly isn't anywhere near the numbers that you suggest.
I'd love to see that kind of power usage in reality; however, I seriously doubt it based on the last 20 years of CPU and GPU progression.
See here, a 4.2Ghz 2700X is around 200W at 1.4V and they had to switch to a much more powerful cooler to stop it throttling.
https://www.gamersnexus.net/guides/3290-exponential-ryzen-voltage-frequency-curve
The Uncore die is a distraction, PCI-E and memory busses were never overclocked with the core frequency, they were just inconveniently on the same silicon and now they have been centralised in the same 12nm process they used in Zen+ so the main power saving is in the die shrink of the cores.
Intel have made little change in power usage from 32nm to 14nm+++++++ , a 2600k @ 4.7Ghz is around 100W, a 9900k at 5Ghz with twice the cores is around 200W so per core consuption is fairly static, you can argue vs IPC there are small improvements but no significant step change so the evidence suggests that smaller process do not provide dramatic power savings at high frequency.
Smaller processes increase the number of dies per wafer and aid costs while allowing some improvement in a combination of power usage and / or frequency. AMD have held TDP static and made modest increases in frequency across the 6 and 8 cores SKU's with the higher core SKU's taking a hit in base clocks.
What you suggest is that AMD now have double the cores of a 2700X at 7nm and they now run at the same ~ 4.2Ghz frequency on 25% of the per core 12nm power budget.
I think I'm being generous very generous at 200W which is 50% of the power budget and way over the 3.9Ghz all core frequency AMD spec for the 3800X @ 105W TDP.
I can absolutely believe that a 16 core 3950X at it's base frequency of 3.5Ghz can run at 5.5W per core, but power usage scales exponentially with frequency so at 4.2Ghz it will need decent cooling and dissipate way more than 105W. At 4.2Ghz - no chance of 5.5W per core.