This is going to result in the loss of a lot of vintage software.
Think about it, right now you can download old games and applications from the 90s to fool around with you on your 90s-era retro PC. You can play those old games and enjoy the nostalgia.
If Apple does this, nobody will be able to download and play games from the early years of the app store on older iOS devices. A lot of this software will be lost forever, since there's no archive of it out there and even if there were you need to jailbreak to load it up.
This policy is really bad for historical preservation. Apple really should re-think this.