During this generation, Nintendo has suffered a really bad case of lack of 3rd party, specially on the WiiU. And that has casued a lot of people to blame the lack of games on the system as the main reason of WiiU's lackluster sales. And that is an interesting point. It's true that Nintendo was unprepared the first years because they didn't expect HD developement could need so many time and resources, and that slowed the software flow down. People expect Nintendo to improve their software output (and considering the lenghts of some of the WiiU's droughts, justifiably so) in both handheld and home console. With the rumours of Nintendo making a Fusion ecosystem that combines both HH and HC software, Nintendo could speed up their developement times. However, a lot of people say that 3rd parties are the key for a healthy lineup, and they aren't wrong.

The lack of 3rd parties have made the WiiU look at the eyes of the consumer as not as worthwile purchase compared to other systems. However, 3rd parties have steadily abandoned Nintendo's home consoles, their excuse is that the sales don't meet their expectations (whoever's fault is that is another topic entirely). So even with Nintendo trying to talk with developers to convince them to develope for the NX, they could "pull a WiiU" again and abandon the system, no matter how good it does.  Wester developers have gotten used to release anywhere but Nintendo systems, that makes the fans of those titles go to PS-XBox-PC, so when they release one of those games on Nintendo platforms they don't sell well because their fanbase is already elsewhere, and that makes them not release anything on Nintendo, and it becomes a cycle.

So, if the same thing happens once again, could Nintendo fill the gaps on their library by themselves? Maybe they can't access to AAA franchises like FIFA, CoD, AC, GTA... but they could always create new IPs that catter those audiences, or use already existing ones to do the job or make deals with smaller developers to get exclusive titles, to satisfy their existent userbase and make the system unique and more attractive at the eyes of the consumer. Fifa isn't on the WiiU? Make a Mario Strikers. CoD isn't on the WiiU? Make Splatoon and Devil's Third. Assassins Creed isn't on WiiU? Create a new IP that could take its roll on the console. TES/Fallout aren't on your consoles? Make a Xenoblade and other open world RPGs. Street Figter/Mortal Kombat (Non-Smash 2D fighters) aren't on your consoles? Help somewhere funding a fighting game for you, ask Capcom to revive DarkStalkers (or if you're crazy enough, ask Disney to make a Nintendo vs Disney, make it happen. It could use both Infinity and Amiibo figurines, so profitable for both). Minecraft isn't on WiiU/3DS? Don't be ridiculous, Nintendo, get Minecraft, it's everywhere but in your consoles.

For every big franchise that skips Nintendo systems, Nintendo could get something to substitute them. That way, the excuse of lack of games would be gone. If that strategy attracts costumers again is the question of the day.

If 3rd parties abandon Nintendo once again, could Nintendo make up for this by getting their own particular games on those genres? Would the consumers regain interest in Nintendo again, or the big names are the things that drive hardware?

why ask such a silly question?

people are still massively interested in Nintendo's dominant handheld and just last generation Nintendo was the leader in home consoles

obviously the current issue is their actual system, people don't seem to love it. but the interest and following of Nintendo in terms of brand and IP's and characters is obviously alive and well

literally the majority of Nintendo consoles have been successful and most of them did not have THAT blockbuster of third party support

How in the devil are Nintendo supposed to realistically arrange that? Where would they get the resources to create answers to every big third party franchise? At best they could maybe muster making one game as somewhat of a counter to each of the really huge franchises, but that would still leave them with only one game in a genre that every other system has tons of games in.

I was asking mostly in two regards:

-Nintendo's home console. I believe Nintendo will apply the Fusion idea next gen, but if the sales of the home console part are WiiU levels or less again, we might just see Nintendo focusing on handhelds that could be connected to the TV. Most of those AAA titles from 3rd party I was talking about sell better on home console, so substituing them should impact the home console sales more.

-Nintendo's ability to create new IPs. If Nintendo wants to replace games like Assassins Creed, Dark Souls, Uncharted or GTA, Nintendo will have to create something that attracts both their existing userbase and fans of those titles that may pick up a NX just to try them. Examples like Splatoon are astounding successes, while cases like S.T.E.A.M. are not. Specially with genres prefered in the west, like the shooters, action adventures or the WRPGs, Nintendo needs to create new franchises or at least make attractive spinoffs to catter to those audiences that don't normally go for Nintendo content because their favourite genres are elsewhere.

Nintendo isn't capable of making hundreds of big games per year, sure. But imagine if Nintendo makes a game similar to, per example Skyrim. Imagine that Nintendo creates a medieval-fantasy open world WRPG, and because Nintendo's name is attached, sells really well on the system. That could cause two things: one, more interest from the userbase to games of the same genre, and two, proof to 3rd parties that games from those genres sell well. Nintendo can't push effectively a console all by themselves, but they need to set an example and show other publishers that their userbase do buy games. I'm pretty sure that, if there were more cartoony shooters on the market, some would try to release on the WiiU after the success of Splatoon.

I never bought a Nintendo system to play 3rd party games. I buy a Nintendo system to play Nintendo game. My issue with the WiiU which is now gone was the price. If the price dropped to 200 and a pack in game I believe they would start to move pretty fast. Someone I know sold me his WiiU with 2 games at that price and it was an easy call.

Maybe, but it would be serviceable either way. If it attracts 3rd party, you win more games and more atention to the system. If doesn't attract 3rd parties, then that game has no competition of other games of similar genre and it can sell unoposed, Nintendo fans get a new game and Nintendo still gains a new IP and erases the myth that Nintendo only rehashes content. Anyway you look at it, it benefits Nintendo.

If the price is low and it is interesting.

Just going to say that you are talking about spending a ton - and I mean a TON - of money, I'm all for Nintendo expanding their operations and buying franchises and so on, but to suggest they output through their own studios and exclusivity deals the equivalent of multiple major 3rd parties? And market all that? Your talking about spending hundreds of millions of dollars. Billions potentially, even with Nintendo's high efficiency. I do think they should up their game on exclusives even more next gen in variety, timing, and marketing. But matching all the major 3rd parties? That's so much work it's mind boggling to contemplate.

I'm not really suggesting Nintendo should spend as much money as other AAA titles. One of Nintendo's advantages over the competition is that their games cost much less than most of AAA multiplas and exclusives. However, even if Nintendo doesn't spend as much as the rest doesn't mean they shouldn't touch genres dominated by AAA games. I'm sure Splatoon costed less than the lates CoD, but the possitive effect on the WiiU is still noticeable. Nintendo needs more games like it. And also, they don't need to carry more than one risky project at a time. If Nintendo tried to make three new IPs and market all of them at the same time it would hurt the sales of all of them. But one at a time wouldn't hurt. Maybe a new IP or a risky collaboration per year could fill a lot of holes on Nintendo's library.

And, yes. Nintendo should improve its output. Making a Fusion system would be a step in the right direction, but havin a couple more studios wouldn't hurt them.