People buy GTA with their current gen consoles. Its as easy as that. Even if they had it on last gen. GTA V sales very closely follow PS4/ XB1 hardware sales.I don't think it's even possible to transfer shark cards so I wouldn't bet on that explanation being right, but it seems near impossible for any video game to sell this much without smartphones and without being PC focused.
Eh there's no way that's causing any significant sales. GTAV isn't growing the industry, its just a requirement for about 1/3 of people to pick up with their new PS4/ XB1. Its been the same for years.
A constant 1/3 attach ratio seems impossible. That should be decreasing as more games release on PS4/XB1.