I think people are starting to underestimate the impact a MH title on consoles would have if released worldwide. Do you honestly think a PS4/Xbox One version of the game wouldn't sell?
Not really a question of "would it sell" or not, it already showed the ability to sell over a million in the west on the 3DS, but more of a question of is it worthwhile, monetarily and looking at development costs, to make said game at the cost of your established fanbase on handhelds and, moreover, where you domestic market is a dilapidated tirefire outside of the 3DS.
Would they sell more than what they already sold on the 3DS in the west?
Would they make up the lost sales in Japan?
Would they make up the orders of magnitude larger budget and expensive assets?
Obviously, once the 3DS retires and the next generation handheld launches, things become much murkier.