I don't dispute that M3 can have a very good value proposition. Even apples to apples (ie. same mm2, same process, same watt) it might even say still have say a couple 10% efficiency AND power advantage. I don't think so, but even if it does I don't consider it a huge deal, not a bigger deal than x86 legacy.
I just dislike when people pretend it's all about processor architecture when system integration, node advantage and ability to spend more mm2 (at lower clock) have such a massive impact. AMD chiplets are not power efficient, they are cost effective ... but that has little to do with x86. 7945HX systems are much worse than 7840U systems at power gating and much much worse than Apple systems, but again that has little to do with x86.
ISA is the least of the problems of (windows) PCs and the least of the advantages of Mac. Other factors are much more important for efficiency and other advantages.