Nintendo games are leg games. You’re thinking of Sony where most fans buy primarily at the start, but Nintendo games have always been more of a full race in comparison, at least for the most part.
Not to mention, Zelda is well beyond its original userbase now and is selling to newcomers/new fans, and selling well at that. It’s already the best selling game in the series so what you said is irrelevant at this point anyway. That comes across as an excuse to believe BOTW will somehow stop selling as well all of a sudden, but again, it’s already the best selling in the series, has been out for over a year, and is still selling great without any deals or editions. There’s no reason to believe that’s going to change as of now. It’s clearly an evergreen title that is going to sell well until the system is dead. Once this game gets everything that Horizon has been graced with, it’s possible enough to reach 20 million.
1 - Not all Nintendo games are ever green.
2 - Zelda previous numbers are way below 20M to consider this as something more probable than not hitting 20M.
3 - And there is a very big difference between selling 10M in first year to 20M LT versus suddenly stop.
1 - BOTW is evergreen, and Nintendo themselves are calling it as such.
2 - BOTW is selling FAR beyond previous Zelda numbers and cannot even be compared or based off previous Zeldas at all. 20 million at it’s current pace is possible. Not guaranteed, just possible at this current rate.
3 - It sold 10 million in barey over a year at FULL price. Most games need to do massive price cuts and bundles/deals to do that, but Zelda has not. Again, this is possible. 20 million is around max that I would expect, but it’s absolutely possible based off what we’ve seen from the games performance thus far. We shall see.