Good point, but do these settings need the latest M-series chip then, too?

No, but if you're on a 3-5 year refresh cycle and this is your year, it'd be lame to not have the latest chip!

It's simpler and better for both hardware makers and buyers to just keep refreshing instead of trying to get clever about who deserves the current series of chips in their form factor, assuming the refreshes are of similar cost, utility etc.

These places aren't going to care about saving $200 on a machine that will return an order of magnitude or more than that in sales per hour