Oddly enough, this is why I stopped buying iOS devices. With my old Android phones/the one Android tablet I got I was able to install something useful and pared-down once they became older and unsupported. They work fine as readers/browsers on my home network or as "fancy" remotes and local-network media players.
The only old iOS device I haven't sold/tossed is an iPad 2 which is unbearably slow for most things, and I can neither downgrade the OS or install some lighter alternative. Plus it needs a new 30-pin power cable but I haven't gotten around to buying one because all the other old devices just use one of a pile of USB cables I have stashed around.
As far as I'm concerned, at least in terms of repurposing older devices, iOS is like the old consoles where it's essentially stuck once there are no more "official" updates. If it boots Android, there's a decent chance I can install something custom on it years later.
The only old iOS device I haven't sold/tossed is an iPad 2 which is unbearably slow for most things, and I can neither downgrade the OS or install some lighter alternative. Plus it needs a new 30-pin power cable but I haven't gotten around to buying one because all the other old devices just use one of a pile of USB cables I have stashed around.
As far as I'm concerned, at least in terms of repurposing older devices, iOS is like the old consoles where it's essentially stuck once there are no more "official" updates. If it boots Android, there's a decent chance I can install something custom on it years later.