We would have to calculate the tipping point, that means the amount of software sales that make porting a game for the console worth it, that changes from company to company and game to game, but HW sales for the console does matter to the publishers, just not too much.

Let's say that around 3% of the Wii U owners buy any particular third party game, if the installed based for the Wii U grows to 10million units, 300k sales can be expected of a decent-good third party game, it is enough for a company?, well as I said before it depends. Now if the installed base grows to 20 millions, expected sales are 600k it is worth it now? maybe for more companies or games. How much it matters the sales? very little, around 3% of the install base actually matters to the third party publishers, but they do matter in the long run.

The problem is that porting is becoming less and less of an option as they are creating less 360 and PS3 versions of their games, and porting from PS4 and One is more expensive so you need to sell even more copies to make it worth it.

It's like 4 inches bigger. To support full size DVD discs.

Keep telling your self that.. :)

First.. it would not be "magic" for last generations clear winner... Whit the most loved brands.. And people (casuals too) know always deliver good quality games.. And curently selling second best.. and also  almost 25% more market share than Xone.. To be second lifetime.. but just keep telling your self that.. :)

Second.. No.. we do not have enough data to support, that 3. party can't sell on WiiU..

To the topic:

YES...  When WiiU reach 10 mill (and 15-20 mill in 2015) it will for... 100% sure mean more 3. party.. And i don't see why you are talking otherwise..

WHEN 3. party can see that there is +1 mill sales.. 3. party will come.. (if they turn down the money.. they get fired)

Of course selling more consoles will help. It will not have more Third Party Support than PS4/XONE, but it will for sure improve their sales if the user base is bigger.

Well, duh. It was the same for Wii.

The next Nintendo "hardware" if it is indeed a fusion platform (ala iPhone - iPad) will probably finally get OK third party support.

Japanese support like Monster Hunter, Dragon Quest, Bravely Default/Final Fantasy spin-offs/Youkai Watch will likely continue there. But now you can play these games on the TV if its a shared ecosystem. 

And for Western third parties, if Nintendo uses say ARM + Qualcomm because of the needs of having to make a chip for a mobile and home platform, that could spur decent support from them too.

It would be one place to support "Nintendo" rather than in the past, the Nintendo handhelds had the userbase Western devs liked, but the consoles had the better specs/tie-ratio that Western devs wanted, so it watered down the Western third party support for both I think.

If you give Western devs one unified platform that checks off their "Nintendo box" from their "todo list" I think that will be appealing to some devs at least. Maybe EA will return. I wouldn't mind being able to play a PS3/360 caliber game of NHL 16 or Madden NFL 16 or FIFA 16 on the go. 

Problem is, they don't even release dlc for the Wii U. I mean look at Black Ops 2!

Do you really see DQ and Monsterhunter not making there way to PS4 eventually ? those games dont need nintendo to release on moible or tablet.  Either way they are likely bolting for greener pastures.  

once support is cut it never comes back the same gen.  

PS4 is selling like crap in Japan, I don't see a huge incentive for developers to jump ship when both series' rely on Japan for like 80% of their sales.

I doubt the PS4 even reaches half of the 3DS' LTD ever in Japan. 

Japan's moved on to mobile + handheld, there's no changing that now. MH4 sold 3.3 million on 3DS first ... that's not exactly charity money, there's still a very strong incentive to not look past that type of revenue. If they want to make mobile ports 2-3 years after that, they're free to do so. 

To PS4? PS4 is dead in Japan. Why would games who's main sales come from Japan move to a console that is dead in Japan?

Sony is NOT greener pastures. Wait until they are out of debt... which will take a while unless they screw up again.