Usually not, A lot of companies use engines that are very diverse and have support for both consoles. let say you build a game in Unity. It has both Wii U and PS4 support, It's just a matter of optimization from there 

MS and Sony are using them because it's easy for developers to make games for, not for efficency. Efficency in technology is just a faster way to do things. powerPC will always have the advantage over x86 in this category. It's the difference of sending 3 large men carrying a ton of barrels each (x86) and  a ton of men carrying a single barrel each (ARM/PowerPC). Both groups will finish their task, but the people carrying single barrels will be done first. The RAM you put in to it is the steroids. 

X86 just don't fit in to Nintendo's philosophy. Hell the Wii U uses less power than the Wii. There is always more to consider than raw unadulterated power. Look at Sony last gen. The cell had huge potential, and it wasn't used by anyone except internal devs. 

I mostly meant the AAA western titles that literally have never been a major factor on Nintendo platforms, I later said they would still need the Japanese 3rd party support that there handhelds usually get.

But ur wrong Nintendo has amazing software output, here are the major games they have released from November 2012-May 2014

Paper Mario, Animal Crossing, Pokemon Mystery Dungeon, New Super Mario Bros U, Nintendo Land, Game & Wario, New Super Luigi U, DKC Returns 3D, Luigi's Mansion 2, Pikmin 3, Wii Party U, Wind Waker HD, Wii Fit U, Wii Sports Club, Mario Party, Mario Golf, Link Between Worlds, Pokemon X/Y, Yoshi's New Island, Kirby Triple Deluxe, Mario Kart 8, DKC Tropical Freeze, Tomodachi Life, Super Mario 3D World.

Thats well over 1 game per month and I might be missing a few. Nintendo does have excellent software output, the problem is they have to spread them out on 2 seperate platforms.

Cell phones don't use x86, but that hasn't stopped PS4/XBO from using it. This is about BC, not ports. The hardware needs to be able to run the old Wii U games you already have, not port them. I downloaded MK8. I should be able to play that same copy on the Wii U's successor, and maybe even the 3DS successor.

Backwards compatibility with the Wii U ... Nintendo's least successful and most niche console ever is not a big priority IMO. If they can ease the burden of porting games, so be it.

Price of the next handheld is much more important, one of Nintendo's biggest blunders this generation was using highly propietary components (Power PC + highly customized GPU) instead of using more economical modified off-the-shelf components. 

It's why they can't make money on the Wii U even now, whereas Sony who used a more PC-like architecture is already not only profitting off the PS4 but seeing bigger than expected drops in hardware manufacturing. 

No one is going to give you a sweetheart deal on components that only you use, even if they're not as powerful as what others are using. 

What Nintendo is doing today is actually the antithesis of what Yamauchi did with the NES. 

That's a year and a half. I won't even begin to list all the 3rd party games that Nintendo has missed in the same time span. That isnt nearly enough. There isn't enough variety and there aren't enough big budget titles there.

It was a big priority for the Wii. I doubt a 5m unit difference will break their decision on that one. They've already made it clear that making the hardware transfer as painless as possible, and keeping consumers with each new hardware generation. They don't want to hit restart with each new generation. Losing BC is the perfect way not to do that.

Each console after the NES sold less and less under Yamauchi. 

So Nintendo has bad software output because they cant match the total of every 3rd party developer combined?

Also u seem to be ignoring a major point I made in both previous posts, they will still have excellent Japanese 3rd party support

Well the Wii U results speak for themselves, not only did Nintendo manage to make a console only moderately more powerful than a 7 year old XBox 360, they managed to lose money on it too. 

It's time to stop making hardware based on niche ideas ... like backwards compatibility and having a console that's small and only runs at 33 watts because Japanese housewives and eco-friendlies that like low power consumption. The general gaming audience doesn't give a f*ck, yet Nintendo expended all that effort into these areas that yielded a more expensive console to mass produce. 

If they want to make a console for an audience of like 10 million people though, that's their business. It's just not very good business. 

There's really only 10 Wii U games that maybe are worthwhile in terms of having for BC anyway -- Mario 3D World, DKC, MK8, Smash, Zelda U, Xenoblade, Bayo 2, Splatoon ... the rest really ... if you can't live without Mario & Sonic Sochii games ... c'mon. If they can create some dev tools that make it easier to port the 10 or so Wii U games that the masses really give a crap about, then it's better to simply go with the most cost effective for power chip. 

BC is not a niche idea. It's an idea that PC's and smartphones use to universal success. You don't get to chose what games are "worthwhile." Any game someone purchases is worthwhile when it comes to BC.

Backwards compatibility with the Wii U is a niche idea. It's a niche library. Nintendo can't make decisions based on the 10 people who just can't live their lives without playing "random Wii U game that no one bought the first time around". 

If they can create some dev tools that makes for easier porting then they can take the 10-12 Wii U games really worth porting, and port those, maybe just hire one team to handle all that and leave it that. 

Choosing a more expensive/less efficient CPU or GPU for this reason ... well, lets just say if they do that, then Nintendo really has no right to complain about hardware costs biting them in the ass later on. You make stupid decisions, be prepared to pay the piper. 

PS4 has no backwards compatibility yet its kicking the Wii U's ass every which way.