Who buy a ds never has a problem to paying 40 dollars for a game i don't know why they will switch into smartphones.
Smartphone game could never be better than a handheld game because if the quality increase the budget increase so the price of game will be more expensive than 1 dollars and smartphone gamer won't buy this games.
PS4 - over 100 millions let's say 120m
Xbox One - 70m
Wii U - 25m
Vita - 15m if it will not get Final Fantasy Kingdoms Heart and Monster Hunter 20m otherwise
3DS - 80m