I suspect they did the same to older iPads. I have two iPads, one of the older iPad 4 with the larger charging port and a new thin iPad. At some point there was an update and the old iPad slowed to a crawl on the internet. The apps worked fine but surfing the net became all but impossible.
Typing this on a 3rd generation iPad that seems as capable as the day I bought it. It’s forever topped-out at iOS 9, but it still runs just fine.
The wife’s older IPad had the same problem. To whomever above who said MS does this, you’re full of it. Never had these problems with MS and I know of some small businesses still running strong on Win 95.
This is the way Apple keeps the fan boys and other sheep continually buying overpriced upgrades, by making their current systems unfriendly.