With some systems, you can attribute a large percent of their success to one groundbreaking title; Super Mario Bros for the NES, Tetris for the Gameboy, Halo for the Xbox, Wii Sports for the Wii, etc.

Which single game do you think contributed the most to the Switch 1's meteoric rise to 155 million consoles and counting, and what's your reasoning?

That is difficult to answer, but Ill go with Breath Of The Wild. Just with the expansive world take on the franchise and the great reviews, I think it just made such a great first impression of the console.

Definitely BotW IMO. With it, consumer confidence wouldn’t have been there when Nintendo needed it most. A system’s launch is very important to get right… just look at the Wii U and Sega Saturn.

Breath of the Wild was the perfect launch game. The concept of the Switch was cool by itself, but it needed a strong title at launch to help sell it, and you couldn't ask for much better than BotW. While it's far from my favorite Zelda game (that distinction still goes to A Link to the Past), it's beloved by many and is often considered the best or second-best game in the series by most, and is by far the best-selling entry in the series. I remember reading about how so many people were excited to play it that more copies of BotW were sold than Switch systems that March. That means some people that couldn't find a Switch at launch still bought a copy of BotW for it in anticipation of playing it once they could find a Switch. Now that's hype.

COVID 19

Being hybrid.

Zelda Breath of the Wild. The Switch was easy to preorder up until the Zelda BotW reviews dropped. Right after that it became hard to even find a Switch after launch. Zelda BotW became the first video game to have a 100%+ attach rate for it's launch month.

COVID, though it wasn't considered that fun by most people.

BotW is the only answer for sure.

Though the Animal Crossing/Covid combo boosted Switch into hyper sales mode for a couple years there and made the Switch into a whole cultural moment for a while, it was BotW that set it all in motion and made the Switch a must-have system and continued to be the one game you absolutely have to get if you own a Switch.

I would say BOTW because it was the one that started Switch's success, even though MK8 DX & ACNH proved to be far bigger system sellers.