Just keep in mind that scaling things will change power efficiency. Like the Vega gpu architecture showed so clearly - which could be quite power efficient, but the Vega graphics card released were ridiculously power hungry, it seems because they missed their performance target and thus got overclocked out of their power efficiency range.

I'm not sure that they can easily add more cores to the M1. If they can, that would also raise the TDP. And adding more cores does not increase performance linearly, even if the architecture is made for it.

Also keep in mind that comparing it to 14nm Intel processors with an architecture from a decade ago is a fair comparison when comparing M1 vs prior Apple products, but is not a fair comparison when comparing it against what x86 can do in general. You would need a modern x86 processor targeting the same watt usage to have a completely valid comparison. As discussed in the thread above.

So yeah, it's a great processor for its target. And it likely will also be a very strong processor when scaled up - it bodes well for the future of ARM. But don't extrapolate the performance too linearly, that is likely to be misleading.