Bringing up the Wii's library is irrelevant as far as a successor goes as devs no longer have the choice of choosing platforms, saying Xbox and PS4 will be all super powerful and make things seem old is all well and good but the problem behind this logic is the development cost would be through the roof. This is the problem Sony and MS will face the blue crowd will always follow Nintendo as things stand because they're a brand to them plus Nintendo caters to them consistently, a console of PS3/360 power may not be the most powerful by then but it'll be sufficient for devs to port over multiplatforms with little hassle, be cheap both in price and development cost by then and this is all Nintendo needs.
Developers can't bet against Nintendo's next console like they did with the Wii not with rising costs.
