If you read about these particular chips, it should be startlingly clear that they are much more efficient than the Intel chips they replace.
In this article:
> Apple doesn’t advertise any TDP for the chips of the devices – it’s our understanding that simply doesn’t exist, and the only limitation to the power draw of the chips and laptops are simply thermals. As long as temperature is kept in check, the silicon will not throttle or not limit itself in terms of power draw.
> The perf/W differences here are 4-6x in favour of the M1 Max, all whilst posting significantly better performance
Read page 3 of this article. They really do cover a lot of this.