@Shadow1980
Just to play devils advocate, the Wii U could still win this gen. If we imagine the following; PS4 dominates the 8th gen till the end of 2015 but ultimately fails to sell enough to be considered a massive success failing to hit 20 million mark, selling only 18 million by the end of 2015. The Wii U ends up taking second place thanks to solid first party games (Smash, Bayonetta, Zelda, Metroid) hitting aroud 14 million. Finally the Xbox One slips into third trailing with consumers reacting badly to timed exclusivity deals and lack of variety, big names like Halo and Gears help push it to just over 10 million by the end of 2015. This could cause multiple developers to decide to release cross gen, or like Ubisoft have with the Assassin's Creed franchise, have a game for PS3/360 in the works also. This could artificially extend the life of the last gen and slow down the current gen.
In this situation, if Nintendo announced something big; a Pokémon Wii U game with internet support that uses Amiibo, an add on to play DS/3DS games on the Wii U, or a plan to buy-out Capcom... just to name a few possible ideas. If Nintendo did any of these (or if we're being bold, all of them), they would likely gain significant sales, regain third party support and maybe get some of the more popular games ported over as "game of the year"' editions with included DLC. Especially if PS3/360 support is still widespread. If Sony, who's currently struggling financially, can't afford over the next 18 months to push exclusives, it may seem as though PS4 has "lost steam" and people may avoid upgrading to the 8th gen machines entirely because they can "just get the PS3/360 version".
In this scenario PS4 continues along, helped by it's strong start it maintains market relevance but struggles in later years as Sony lacks the financial clout to build first party studios or buy exclusivity rights and more tech savvy gamers start moving to PC gaming as high performance games simply can't run on the outdated hardware of consoles. It may sell decently in lifetime sales but not enough to make Sony profitable with it's other divisions all losing money, this may be the point where Sony downsizes and abandons everything except Playstation to becomes just a gaming company; but at least this way it's profitable. Simultaneously, Xbox One simply peeters out and becomes a niche machine much like the original Xbox was, known for it's odd exclusive but little else. Microsoft pulls funding from the Xbox division, (which has historically never been very profitable for Microsoft anyway), and leaves the console market completely, creating instead a set-top box similar to Rouku or Apple TV and making a Steam-like Client for it that's compatible with Windows. They will likely keep the Xbox name for brand recognition. This would leave Nintendo in a strong position to dominate the now far smaller home console market, perhaps with a console-handheld hybrid. Maybe a successor to the 3DS that connects to your TV via a wireless receiver for home use.
The generation lasts till 2018 with PS4 selling 35 million, Wii U squeezing ahead with 41 million (just short of SNES figures), Xbox One barely tops 22 million lifetime sales. The PS3 however comfortably tops 105 million sales and the Xbox 360 manages to get just short of 100 million as cheaper budget models become popular. With combined sales of less than 100 million, the 8th gen is remembered as a collective failure, underpowered and mismanaged, but Sony, Nintendo, and maybe a newcomer or two go into 2018 with new consoles for the end of 2018.
Likely? No. But possible... entirely so.
Sometimes it's fun to have these little thought experiments.