There’s lots of ways to make existing hardware more efficient at the cost of performance. Under-volting the CPU and RAM (or just putting them in “efficiency” mode) can probably save more electricity than you lose in generational improvements. Considering how much more powerful PCs are compared to SBCs, you’d probably still have better performance than an SBC. Also, a more powerful CPU that takes double the power but as a result can idle for more than 50% of the time would be more efficient than a less powerful CPU never idling.

There’s a lot of other variables (like idle power draw, efficiency at various power levels, idle latency, etc), but in general I think your statement would be inaccurate at least 60% of the time.

It’s a distro that only cool people know about. I’m sorry you had to find out this way.