Moore's law might have stopped with the clock gains when Denard scaling gave out but we've still got energy efficiency gains. Koomey's law[1] is holding strong. I don't know if it'll get us all the way to Landauer's Limit[2] but I hope so.

[1]https://en.wikipedia.org/wiki/Koomey%27s_law

[2]https://en.wikipedia.org/wiki/Landauer%27s_principle

It's probably not a great comparison to compare the theoretical numbers of Frontier to the achieved numbers of the green 500. The achieved flops is pretty much always considerably lower than the theoretical flops. Titan is a 27 PFLOPS machine that achieves 17.6 PFLOPS, sequoia is a 20 PFLOPS machine that achieves 17, summit is a 200 PFLOPS machine that achieves 143, ...

~ 37 GFLOPS/W is probably a better projection if we assume (out of nowhere) that the theoretical/achieved ratio of Frontier is comparable to Summit (75%). Still very impressive.

GPUs help considerably here, taking a look at previous ORNL machines:

  Jaguar | 2.3 PF XT5 (CPU-only)      | 7 MW for HPL
  Titan  | 27 PF XK7 (1:1 CPU to GPU) | 8.2 MW
  Summit | 186 PF (2:6 CPU to GPU     | 8.8 MW

Overall, substantial changes in computing power and 10%-20% increase in power.