You’re using a PC from 1992?
I'm not using a PC from 1992 because I consider them to be too old, not because some company unilaterally decided that it's now to old and that it is now junk.
My PC have parts from 2012 and is still working fine (I'm using Linux but tbh, even under windows, it works pretty well). Good luck running up to date apps on a 2012 iPad. My 2012 PC is up to date.
Most 10 to 20 years old PCs can run some light (and up to date !) linux distrib and can serve many purposes ranging from lightweight terminals to educational material in third world countries. Heck, with the right software setup, most are still really decent office computers. We are not in the 90-2000s anymore where every year your new computer was vastly faster than the previous one.
An out of date iPad is just electronic junk. Not because it is not fast (it's even as fast as when you bought it) but because it's not yours anymore.
I don't think so.
The only way they're using it is the same way they're using a Commodore 64, as an antique.
A 486 running Windows 3.1 with Cubase 1.0 exclusively for MIDI running in Standard Mode is far superior to any modern machine with respect to timing. Also, MIDI software hasn't evolved that much over the past couple decades.
Perhaps it even rivals an Atari ST
DOS/Windows 3.1 is still good for timing sensitive applications.
Nowadays MIDI interfaces are usually USB. But an ISA card or a parallel port will yield better results.
On modern computers, MIDI generally feels slightly off, and not as musical, but for the most part 'good enough' for the vast majority.
But the oldest iPad from 2010 will still be able to get the “last supported version” of apps from the App Store, still works with old versions of iWork, streaming video apps, Spotify (at least it did a couple of years ago), you can send video from it to any device that supports AirPlay and print to any AirPrint printer.
But to respond to your second point, I believe that Apple has REMOVED apps from the App Store that were previously available to download. For example, I was not able to download on my old iPhone 4 the latest working GarageBand for that device, because it was deleted. This is not the only app that I have not been able to download, because it was REMOVED FROM THE APP STORE.
But I think the point you are missing is that if Apple decides that these devices are obsolete and they will not support them, they should be willing to at least release documentation that allows people to write/install whatever software they want on those devices.