I've seen this asked elsewhere so here's a genuine attempt at an answer. Oversimplifying it for a second, I think Apple has a few different buyer categories that it targets with both its machines and (most importantly for this question) the upgrades that it offers.
The first group is in the market for an Apple machine but will mainly get the entry level spec as they don't necessarily care about the tech specs (or they're priced out of the higher end of things.) Then there will always be a group who look to buy the best possible computer for the money at the time; these people wouldn't accept a MBP13/iMac/Mini/Air, and will only opt for a MBP/Studio as anything less just doesn't cut it.
Both of these groups are miles apart in terms of their needs. But there's quite a significant gap in the middle, and that's where the importance of the upgrade in (some) Apple customers minds comes in.
This other group is trickier to pin down. You can't say they should buy a Pro machine, because there will be some who just prefer the form factor of the non Pro/Max/Ultra machines, including the Air. But more generally, this group is not neccesarily wedded to the Pro tag, but they are absolutely not satisfied with a base level machine. And heavily upgrading a MBP13/iMac/Mini/Air can make it feel better as a long term investment.
The M2 Air is interesting because yup, a 24GB/1TB Air costs about the same as a 16GB/1TB Pro. But if you're in the "anything but base" group, if you're commiting to spending 2k, you might prefer the feeling (this is nothing to do with effeciency cores and RAM) of bumping up the spec a long way from base, rather than a tiny tweak to the SSD for example.
Again, purely subjectively, the 16GB/M1 vs 16GB/M1Pro feels a lot simpler to decide between than 24GB/M2 vs 16GB/M1Pro because the 16GB max of the RAM on M1 threw the speed of the processors into the spotlight.