There's also the DRM issue. DVD players pretty much just work. My in-laws purchased a Blu-Ray player, but no longer use it since it refused to play a handful of movies they had rented. They're not going to bother with updating the firmware on their device when they could just watch a DVD instead.
Also, the gravel roads help them to justify the SUVs and pickups they own to drive back and forth to work.
"I'm so glad I have four wheel drive, or I'd never make it out of my neighborhood. It's not even paved!"