They're only 1 process node ahead of Intel. Intel 10nm is roughly equivalent transistor density as TSMC 7nm. The M1 was TSMC 5nm.

And given that there's no way a single process node jump is going to give Intel a 75% uplift in instruction per clock (2 nodes wouldn't give them that either, for that matter), Intel is going to have to clock higher for comparable performance and that's still going to put them behind on power consumption (which is exponential in clock speed).

Which is to say, it's completely untrue that the only reason these chips look good for speed/power-consumption is the process node they're on. Apple came up with a super-wide architecture (way wider than anything we've ever seen in x86-64), and they made it pay off by getting good performance out of a much lower maximum clock, which bought them a ton of power efficiency.