Isn't the screen size difference basically enough between these two? I can't see why the 16" would need more performance, some ppl just want / can carry large computers with them while some other prefer to have something as small as possible.
I have to say if I had any choice I would delay my purchase until the 16” catches up rather than buying a generation behind. If I see specs saying M5 14” is more performant for my workloads than my more expensive 16” I’m even more motivated to delay. Most product managers would be aware of these things.
I can see an overlap with people who want smaller computers who also want max power, but I just would not believe that is a significant group. (again, all personal observations)
I also think the 15 inch MacBook Air filled the non-power-user-but-likes-big-screen niche.