Yes, it looks like the M1 was designed mostly for the MacBook Air. The specs are a perfect fit and it makes a lot of sense, as the Air is their most popular laptop. Having the perfect Air - and the new one is truly impressive - will make for a lot of Mac sales. Also, they also put it in the bottom end MB Pro and Mini. But indeed with the next variant of Apple Silicon, the higher end variations, and other devices are probably going to be supported.