At least, you pay a fee of 25$ and it's on you (or Google). Paying 99$/year and still experiencing some strong frustration at each newer release and change is much more for fetishism
80% of all iOS devices are on iOS 12. An additional 12% are on iOS 11. Any device that can run iOS 11 can also run iOS 12.
By not supporting older devices, you are missing out on at most 8% of the iOS population. But even some percentage of those are able to update to iOS 12.
To target anything older than the 5s means you also have to target 32 bit processors. How much time are you going to spend targeting such a small user base?
Besides, if you have an older version already in the App Store, they can download “the last compatible version”.
How far down the rabbit hole do you want to go? The 4s? The 4? The 3GS? The 3G? The original iphone?
You'd better believe there are older devices out there, and people would use the app store with them, iff the app store would only show you apps (or versions of apps) that still run on your device.
It is frustrating trying to get games on an old iPad for the kids.
I’ve done that with my first gen iPad as late as last year to download a few streaming apps like Netflix, Hulu, and Plex.
As an app developer, it's immensely frustrating to have to keep updating apps to stay on top of the latest SDK.
As a mobile user, I delete apps that get flagged up as battery hogs.
So that leaves me with a fairly simple choice, and I keep stuff updated if I expect anyone to keep using it, and if I abandon it, I shouldn't be surprised when my users do the same.
I think the difference in API stability is a result of the different financial motivations between Microsoft and Google. For Microsoft, the OS itself was the product; to not make the APIs backward-compatible would have meant significantly less revenue and market share.
For Google, the OS is not the product. Google doesn't make any less money when someone continues to run an old version of Android. There is no monetary incentive to make new versions of the OS API-compatible with older versions, nor is there any monetary incentive to make new versions of the OS run on old devices.
Consider also that the cost of upgrading to a new (non-flagship) device in 2019 is much cheaper than in 1995. A typical PC circa 1995 could cost $2000 or more (price adjusted for inflation). Today, you can get an entry-level mobile phone for 1/10 that price. Back then, a family might hold on to a computer for five or ten years, because it was so expensive to upgrade. That makes paying $100 or so for an OS upgrade every few years worthwhile, because it's much cheaper than buying a new PC.