1GB was already barely sufficient even when it was released.It's called learning from the past. That poorly performing 1Gb device was equipped the maximum RAM of *any* iOS device when it was released just 5 years ago. It performed extremely well at that point. You couldn't buy a better ipad (or tablet generally for that matter).
The next year, the iPad Air 2 doubled that RAM to 2Gb and iOS and its apps grew to fill it. You're talking about how current 2 or 3Gb ipads will perform for "many years to come" - in truth that iPad Air was struggling after one year. Although it still runs current iOS, it has for "many years" struggled with insufficient RAM.
I think the current scenario is more akin to the iPad Pro 9.7 having only 2GB. A lot of people blasted it for not having 4GB saying it'll quickly go obsolete. Sure there are some multi-tasking features that were omitted (which weren't particularly useful on the smaller display anyway) but performance-wise, it's actually still doing quite well.