Earlier quoted context omitted.
Most people have no need to compare CPUs between mobile/non mobile or generation. They just need to know if the laptop they're looking at has the high end / middle end / low end CPU. You'd be comparing a new laptop with latest(-ish) CPUs. The i3/i5/i7 makes it plain & simple to know that. You don't need to figure out what the "middle end" CPU is called this year. It's the i5, problem solved.
Right, and this describes the marketing problem. If I already have an i5, why would I need another one unless it's broken? If I have an M1 and they're selling M5's, I'm continually reminded that my rig is out of date.
Samsung quickly learned to play the same trick with their yearly Galaxy S and Galaxy Note releases. That decision probably contributed to the market share they've been enjoying.