The hardcore gamers didn't leave Nintendo. The gamers that play Nintendo i think are usually more open-minded about games and don't play what the media tells them to play.

I disagree. The hardcore are the segment the Wii U has. Its the casuals that ditch it. The bro's were never with them on this or last gen.

Well think of it like Sega. Sega burnt MANY fans with the Sega CD, Sega 32X, and Saturn. By the time the Dreamcast came, most people abandoned them. Despite this, it still managed to sell 10.6 million in 1 and a half years (with the half year being Japan only). On the other hand the Wii U has had a full worldwide release for 2 years and hasn't even hit 9 million yet.

Nintendo fans were abandoning by the N64. By the GameCube they were pretty much done. Gamers simply just don't care about Nintendo as much as they used to, and the fact Nintendo is making many weird decisions (Celda, 3D World, crap online) etc. etc. isn't helping.

Sony actually gets most of its popularity via third party titles. It doesn't really have a first party system seller outside maybe Gran Turismo and Uncharted. 

I abandoned Nintendo for 3 or 4 generations(not sure), but I went back with the Wii U!

Edit: Ok, maybe not abandoned, we just didn't have enough money.

The Madden/COD bros were never really with Nintendo ever though.

The fact is the N64 sold only 32 million, the GC 22 million, but the Wii sold 100 million by focusing on its new audience. Now that Nintendo is trying to go back to the audience that quit buying Nintendo consoles the results are obvious: Wii U is selling worse than the Dreamcast and almost the Vita.

I can tell you the difference. Those system were actually more powerful than the market base console. That atracted a wider audience wich are the tech/graphics enthusiasts.

Nintendo has hardcore gamers buying their system because we all know those casuals aren't buying it anymore. So 9 million hardcore gamers have kept the system selling anything. Actually that's a lie my neighbors have a 10 and 8 year old and they're the only ones apart from myself in the neighborhood (probably 30 houses or so of varying ages) that have a WiiU.

Nintendo has no problem pleasing its core audience. The problem is they can't expand beyond the tried and true demographic that goes out and buy their consoles.

Nintendo did however abandon its 101 million Wii owners

There aren't that many core Nintendo gamers as proven by the N64, Gamecube, and now the Wii U. And along with the fact that the Wii U has no third party support, its easy to understand why the Wii U is doing as bad as it currently is. 

Well, Nintendo is doing what they can, but Sony and MS are bringing the big guns, that is all, it is not Nintendo or the consumer fault, time are just changing...