Speaking as someone who spent all weekend playing his new M64: Yes, the target market often does buy the cartridge. I've got a brand new copy of Xeno Crisis sitting on my shelf, although Xibalba was a close 2nd. (Tied with Buck Bumble ;) )
That said, there's definitely a crowd that would rather buy a summercart and pirate all their roms. Personally, I'm interested in more thoughtful and intentional electronics, so I'm attracted to the idea of old school "buy the game on a cartridge" mentality.