When you say a game is niche you mean it is niche compared to other games, no one says something is "niche" because more people visit Disney world.

Niche are games that appeal to a very low percentage of gamers, i.e <5%. Not games that appeal to a very low percentage of the world.

So... your definition of mainstream is some arbitrary calculation against the entire human population of planet earth as a denominator. That doesn't work... Why? Here's why:

By your definition, the entirety of the console video-gaming industry is niche because 120 million out of 7 billion (1.7%) is niche. The problem is, your definition doesn't explain anything, it doesn't explain your argument as to why Zelda can't sell 20 million units: "it can't sell 20 million because it's niche, it's niche because I think it will sell only 17 million out of 7 billion." it's textbook circular logic.

A more standard definition of a mainstream product is the association with major fads or trends in a given industry - of which Zelda, and particularly Breath of the Wild, does on numerous accounts; to give some examples: it's a flagship Nintendo Switch title, this generation's most significant killer app, the poster-boy of the action adventure genre, and the successor of one of the most highly regarded video-gaming franchises in history (Legend of Zelda, Link to the Past, and Ocarina of Time have all been highly regarded as the best game ever made in their times and beyond).

Problem is BOTW is still niche by every definition because it is less than 40% as popular a minecraft or GTA. Even COD sells more on a nearly yearly basis. Currently to not be niche you need at least 20 mil cross platform sales, and this will increase to 25+ by end of the gen due to sales inflation.

That isn’t at all how it works, you just create your own standards to dismiss games you don’t like or want to consider mainstream.

Every new major Pokemon release is easily mainstream, and BOTW is on pace to equal that or surpass it. 

One thing is for sure, your rules are yours alone. 

My rules are universal because theyre based on data. Pokemon used to be mainstream. It still is as an entity thanks to its multi media footprint, but the new games arent mainstream. Hasnt been for a long time.

Nahh, not even close. Those legs will come to a stop soon. I mean, all the best, but I just don't see it happening. Funny how the most UNtraditional Zelda game in the franchise is selling the best in the franchise. Similar thing is happening with God of War.

Looks like it's obvious both franchises were lacking something before that many see as appealing NOW.

This is pretty much true. I mean, c'mon...a game selling 10+ million is pretty miuch mainstream. The Last of Us did like what, 15 million across PS3 and PS4? That game IS mainstream. Most will recognize these titles if you mention it to them. Now, a game like Shadow of the Colossus?There is a niche title for you. Well respected and known amongst the cult following who appreciate it, but not by the mainstream public.

As for GTA??? That game is in a class of its own. Even away from the likes of COD. I mean, when a game sells like 80+ million copies that is like what Michael Jackson did with his album Thriller for the music industry. We're talking popular culture phenomenon levels here. Well above anything that is mainstream.

Congratulations, you're wrong.

Your rules exist for you and your perception of data alone. You base it off data but your warped vision with that data is absurd, and thus, not universal. Pokemon games are still mainstream, and the entire franchise as a whole is even more so.

Your mathematical data for how you compare it to the best selling games of today and the past is also absurd and based off your own rules as well. Perhaps using data that exists, but again, warped perceptions, comparisons and conclusions of them. All fabricated so that you can spin OoT as somehow the more impressive seller and not acknowledge games like BOTW and modern Pokemon as ‘mainstream’. Minecraft existing doesn’t change what is and isn’t mainstream, it’s just the king of mainstream, and perhaps in a category beyond, alongside GTAV and the like.

I certainly think it can reach 15M but i think 20M is a stretch too far. Still fairly impressive sales so far.