As someone who owns an OG iPad 1, the benefit of potentially being able to run Linux on it is I already have an old iPad but I don't have a rooted Android tablet. Currently, due to Apple refusing to support it with software updates, and providing no other means for me to update it myself, the iPad is kind of useless.

Not sure this applies here since the OP seems to be only for certain hardware, but...

I'd have bought an android tabled years ago if I had found something that seriously competes with the iPad Pro 12" versions.

Way easier to create software for it, and with more flexibility, for starters.

There are a lot of iPads.