To be honest, I think it's pretty obvious this has less to do with M1/M2 tech specs and more to do with the vast majority of Americans getting a couple checks from the government which basically cover the exact price of a new Macbook.
I know we are all very analytical on this site and love to comment "source?" any time someone infers something from a dataset, but this seems like one of those times we can easily correlate the two.
The lower class who needed those checks to pay rent and buy food did just that.
However there was a large portion of the population who did not lose their jobs and considered those stimulus checks "fun money." Many used it to purchase goods they typically wouldn't have 1k+ to spend on regularly.
Couple that with many working from home, their children going to school from home and needing a laptop, and the sheer boredom factor, I don't think it's a leap to correlate stimulus checks with a huge jump in Macbook sales given the time frame.
Again, you also have to factor in that the check was pretty much exactly what a new, entry-level (aka most popular SKU), Macbook Air would cost after taxes.
Didn't most of these happen before the introduction of the M1 macs ?
The first model hit retail at the end of 2020, and we were already way deep into the covid/wfo cycle, with people buying any laptop available at the time to cover for the transition.
In that respect, the introduction of M1 machines looks to me to happen way after the dust settled on the gov incentives front.