I've been running Ubuntu 16.04 on an SP1 with zero wifi issues such as I've heard going on with the Marvell chipset. I figured it was because the SP1 was old enough that everything had been sorted out by now.
You just priced yourself out of your argument. The people still holding onto XP machines are not buying, as you amended it to say, luxury basic needs machines. They're buying the $300 Windows machine, which really is a basic needs machine because it has what your luxury basic needs machine lacks: a low price point. If you think they really need a New MacBook, lobby for a subsidy or start splashing your own cash to help these poor deluded people.
This is an out of the way device. Do you want to plug your tablet unto your TV and then yank it out whenever you want to take it somewhere? Do you want an old laptop or (god forbid) a desktop sculling around your TV rig/entertainment centre? Some people don't care, some do. You're probably looking at getting a wireless keyboard/mouse on this thing that you can chuck somewhere when you're not using it.
People are too fixated on the specs and 'I can get device X that will work perfectly well in the same capacity!' Yeah, well, you're not making it disappear up alongside or behind your TV.