It’s a good thing though that OS’s 13-15 only needed 2GB of RAM and since then release date of said device being a norm,
I hope the Air lineup in general gets actual 6-7 years of OS Support ( not counting Air 2 because it was released as a “Pro” Device before the first iPad Pro became a thing a year later so it will be interesting for Air 3 and beyond)
the last time Apple did that in terms of both hardware/release date combined was iOS 4 when the iPhone 3G despite it having the same cpu/ram as the 2G and touch 1G ( not touch 2G because that had a much better CPU than the 3G). iOS 6 in ways is a close second but then iPadOS 18 is the second OS since iOS 6 to drop iPads and not iPhones.
The 7th Gen IMO should have had the A12 instead of the A10 when it came out, it would have unified the lineup and made the A12 even more peak like than it is. And I hope 9th Gen iPad and above get slightly longer support given that it was on sale for over a year before it was discontinued
7th gen iPad is the most luckiest iPad in existence, getting iPadOS 18, 6th gen iPad is second for iPadOS 17, 5th gen iPad is 3rd because it got iPadOS 16 given its specs when A9/A10 iPhones got dropped for iOS 16 and but all 3 budget iPads were supported longer than the 8/X though for they’re lifespans.
Again, as I said, year of release, years on sale and specs mean NOTHING for software support.
The only thing that matters for software support is OS of release. End of the story.
I don't believe the air 2 was treated better because it came before the pro existed.
I don't expect the base iPad to get more than 5 OS updates (= 6 OS support)
However, as I mentioned in my predictions from last year (
https://forums.macrumors.com/threads/predictions-for-ipados-updates-over-the-next-8-years.2391411/), I expect the support of the pro to increase to 8 OS updates (so 9 in total) from M1 on, with the air remaining at 7 OS updates (8 in total) and the base at 5 (6 in total). This way M series SOCs will have a better aligned software support since they are first released in the pro and later in the air.
I could be wrong though (and in this case Apple would for maintain the same software support for the pro and the air, with the M2 air being supported as long as the M4 pro, which would not be suprising, just as the loss of support of the 10.5 pro was not either), but I believe it would make more sense and would be a nice improvement now that Samsung and Google offer 7 OS updates too. We'll see, but for now the paths seem quite clear and predictable and the rest is just speculation, generally proven wrong at WWDC (like the speculation that A10X with more RAM would be supported at least as much as A10 with less RAM, which was proven wrong at WWDC as I had mentioned early this year, because again, specs don't matter).