Man, dem Sony fans were right... Nintendo fans do make the most amount of Nintendo doomed threads :/

Well, considering they have losses in the last couple of quarters, I'd say no, it can't keep Nintendo alive all alone. But it keeps them from dropping like a rock. Kind of. They are dropping a little slower, but still pretty fast if you ask me. Hmm. Well, when you fly high, you will fall deep eventually.

Release Dragon Quest XI on the 3DS and bam!  Nintendo saved forever ( specially since Dragon Quest X left such a bad taste in Japan's mouth)!

The 3DS really isnt doing amazingly, I doubt it can do enough to put money in Nintendo's pockets. The year of Pokemon and MonHun in Japan (2013, which was amazing for Software) didn't even beat 2012. Cant see the sales rising YoY which would most likely leave it below the Game Boy. Wii U really needs to step up and become profitable otherwise this gen will be one of losses for Nintendo. God knows what the QoL thing is but that could actually being Nintendo's saving grace

For 2014 the answer is probably yes. The hardware should be cheap to produce by now and the install base is big enough for software sales to flourish. After 2014 thing will be difficult. Nintendo hardware always drops in sales after the 3rd year and 2015 will see lower hardware and software sales. Therefore we might see the successor to the 3DS in late 2015. The 3DS launched in early 2011, so that'll be almost 5 years on the market, a normal life span for a gaming console.
The problem here is the Wii U will be pretty much dead by late 2015 and Nintendo can't afford low handheld sales and a dead home console business at the same time - that would kill their business. When the Gamecube struggled in 2004 they had two successful handheld platforms (the DS was their "third pillar") so they'll need some sort of new hardware in late 2015 (maybe the QoL platform but that one's a big gamble).

My prediction:
2014 - kept alive by 3DS
2015 - new handheld + QoL platform; Wii U getting only token support
2016 - new home console

The cash in the bank will keep Nintendo alive.

Nintendo has a lot of catching up to do. I believe they can last one more round due to banked profits from the Wii and the success of the 3DS. After the WiiU disaster though, it will be a sink or swim scenario for sure.

Keeping alive? - yes
groundbreaking sales, 3DS prints money? - no

No. They posted a loss in the same year they released a new pokemon. That's just embarrassing. They really need to get their shit together.

i think the major profit comes from software. dont seems that 3DS software sales would repeat the 2013 results.
but, wii U software in 2014 seems to be greater than 2013's.
I think it would be enough to survive, but not only because 3DS.