alt Hacker News> Apple launched the M1 in 2020.
which means the M1 was being worked on since at least 2018, I'd bet much earlier than that, for sure much earlier than that if you count silicon which never left the lab.
reminder iphones run on apple silicon since 2010, which means they had to be working on it at least since 2008. they have a lot of experience in silicon design by now.
My point holds even if they started earlier, companies such as Samsung has their own chips and they could also put notebooks on the market.