Ehh, I really wouldn't take the claims in that article at face value. For one, the fact that their benchmark of choice is Coremark is a warning flag, as it's really just aimed at embedded systems. It's a fully synthetic benchmark that has a very small memory footprint (ie it would probably fit within the L1/L2 of a typical modern CPU) and therefore doesn't really represent real world workflows in any meaningful way.
Secondly, their claims are quite ludicrous. They claim:
Immediately, the maths makes no sense. He claims that the M1 is "less than 100 CoreMarks per Watt" but it also is "roughly the equivalent of 10,000 CoreMarks". Does he think the M1 consumes 100W? Besides, his claim on the M1 being 10,000 CoreMarks is also highly suspicious. There aren't published results for it (because it's not designed for embedded systems), but the first result I can find online for it is the person who wrote
the second response here, who got 162,000 for the full M1, or about 31,000 for one of the big cores. Then there's the comparison to the ARM A9 for some reason, which is a 15 year old CPU.
That's not to say someone couldn't design a RISC-V CPU that's at least as power-efficient as an ARM CPU. There are certain benefits to a newer ISA like RISC-V which has less baggage than an older ISA like ARM. If you're curious about the impact of ISA on design, I'd recommend
this Anandtech interview with Jim Keller, who's worked with both AMD and Intel on x86 designs, Apple on ARM, and now RISC-V with Tenstorrent. We may see powerful, and power-efficient RISC-V cores at some point, but the ISA doesn't automatically mean it's going to be a super-efficient core, and you probably shouldn't believe snake-oil salesmen who claim they've managed to beat out the likes of ARM and Apple by a factor of 500x.