Currently, no.

Back in the day? yes

Hmmmmmm, who else remembers those days when Breath of the Wild had an attach rate of over 100% for the Switch?

Pokémon single-handedly revived the Game Boy in the late 1990s (very clear double peak on its yearly sales), so it's theoretically possible.

Well at least you got blood in your Mortal Kombat (first game).

Wasn't that because of Wii U where it sold a little over a million? Nearly 100 percent of Switch owners bought it early on plus some Wii U owners.

Not necessarily win the console war but Mario Kart 8 Deluxe did outsell the Xbox One as well as every console except the top 13 selling consoles/handhelds.

It can't

The reason is console purchases are non-exclusionary. You can have the best and more in-demand game of the generation, if other console has a good (better) list of games it will win nonethless

No, there were more copies of BOTW for Switch sold than Switch consoles at one point.

Super Mario Bros.

I don't think people are mentioning this because NES never really had a competitor, but that's kind of cause they won the war with the first strike. There were other companies that were selling consoles at the time but Nintendo smoked them and Mario Bros was a huge part of that. 

You could make similar cases with Tetris, Pokemon Red/Blue, Pokemon Gold/Silver, and Pokemon Ruby Sapphire. Gameboy never really had a competitor either, but that was largely based on the strength of a few games.

Wii Sports is also arguable although the Wii had a much wider variety of games that did big sales. 

Huh? DKC came out like a month before the Playstation and Saturn. Sega was done with the Genesis.The generation was basically over. And I'm pretty sure SNES was already ahead, especially if you align launches. Definitely WW and probably in the US. 

DKC sold about 4.36 million units on NA according to the data we have. SNES beat the Genesis by about 4.38 million units. Even if we assume every single person who bought DKC bought an SNES just to play that, the SNES still would have outsold the Genesis with or without DKC. Gap is even bigger in Japan, and Sega won in Europe... so I'm not getting how anyone could possible accept that.

Potentially, under certain circumstances, but there has yet to be a clear-cut example of any one game being a deciding factor. Every system that won its generation did so through a number of factors, including price, overall games library (esp. in the exclusives department), and other factors. The closest example that I can think of a game that, while it didn't outright cause the system it was on to win its generation, was arguably a tipping point might be Final Fantasy VII, and even that only applies in the U.S. The PS1 didn't exactly set the world on fire when it was first released, but in Japan & Europe it became clear early on that the PS1 would be the by far the favorite. But in the U.S., while the PS1 started off very sluggishly (like, Wii U-level sales prior to the first price cut), the N64 had a solid start, selling almost as many units in the 14 weeks it was available in 1996 as the PS1 sold that entire year. For the first two thirds of 1997, the N64 had an overall lead, continuing to put up numbers in its first full calendar year that seem to have surpassed first-year sales of everything else Nintendo had released at that point, which would have made it the fastest-selling console ever in that time frame at that point (it was later dethroned by the PS2). But when FF7 was released, the PS1 experienced a big spike in sales, selling 30% more units than the N64 did in the final third of the year. It never fell back behind after that.

Sony put a massive marketing blitz behind FF7, and it worked. The game set records for its U.S. debut, selling 330k copies in its first three days (games used to have much more modest launches back then). It sold another 170k over the next week and a half. But it settled down into something much slower once September passed, taking another 70 days to hit one million copies. Despite its record-setting launch, it ended up placing #7 for the year in the U.S., falling well behind #4-placed GoldenEye 007, which released two weeks earlier. It didn't even make the Top 20 for 1998, while GoldenEye, Super Mario 64, and Mario Kart 64 all did. This suggests that FF7's legs weren't particularly strong, which seems to be normal for JRPGs, including Final Fantasy. So, while it wasn't selling enough past its launch window to explain the spike in sales by itself, what it likely did was put a lot of eyes on the console, and by drawing attention to it and its massive library of games, it may have at least provided an assist to the PS1 to definitively put it over the N64 in the U.S.