David Sparks, writing about what could come after M1:
On the marketing side, I’d be surprised if they call it the M2. Presumably, they will make a successor to the M1 one at some point as the current lower performance/more battery life chip for things like the MacBook Air. Naming the higher performance chip M2 would put them in a weird place where an M3 (for MacBook Air) could be slower than an M2 (for MacBook Pro). The more I think about this, the more convinced I am that the performance chip currently in production will get an entirely different name, like X1, allowing them to have two chips for Macs. (Or possibly three once the Mac Pro releases.)
X1 sounds badass.