I've already predicted that this will in fact happen.

Last spring I predicted WiiU would sell 30m lifetime and be replaced after 4 years (like Xbox). The new console (Wii3) will be on parity with PS4/720 and have some mass market pleasing innovation that makes it a popular choice (which Sony/MS won't easily be able to replicate). I also predict this will be the final big dedicated game console ever released as games will be increasingly console agnostic (PC/Tablet/Smartphone/SmartTVs, etc.)

As Sony/MS won't be launching another console after this coming gen, Wii3 will compete directly with PS4/720 for many years.

No, it really isn't possible. You can't have Wii-like success without diverting resources away from compute power and towards something new and novel. No free lunch.