We have seen massive improvements in power envelope in CPUs in fairly recent generations, to say nothing of the power improvements seen in some generation->generation GPU improvements.
For example, with an improvement to the 14nm process and not a die shrink, Kaby Lake->Whiskey Lake saw low power processors double in core counts (2C/4T->4C/8T) in essentially the same power/thermal envelope. Basically every thin laptop/ultrabook family doubled its core count.
Well... yeah... but they also dropped clock rate from 2.5GHz-ish to 1.7GHz-ish. That could equally well explain the increase in core count at the same TDP. You're gaining about 15% IPC improvement from Kaby->Whiskey [1].
It's an overall improvement, but not as dramatic as "2x cores for 2x perf at the same power"
"Base" clock dropped, but boost clocks remained fairly high. In practice performance gains were quite good (except, notably, for that time when Apple used old power control firmware and had 6C/12T processors underperform their 4C/8T predecessors).
The point of this is that the significant improvement from Kaby Lake to Whiskey Lake involved only small architectural refinement and updates to an existing process, so much larger performance/power improvements should absolutely be expected from an entirely new process plus architecture refinement.
For example, with an improvement to the 14nm process and not a die shrink, Kaby Lake->Whiskey Lake saw low power processors double in core counts (2C/4T->4C/8T) in essentially the same power/thermal envelope. Basically every thin laptop/ultrabook family doubled its core count.