With NSMB U Deluxe and Mario Maker 2 already on Switch I'm not sure they will release another 2d mario. But whenever they do I hope to see a fresh take that isn't NSMB.

If a new 2D Mario game was right around the corner it legs could get cut off hard, but since I expect it'll be a while before that and U Deluxe is selling damn well as of late, I expect it to cross the 15 mil mark.

Bonus question: Oh, it will happen, the only question is whether it'll be "New" or new.

I went with 11 to 12.9m because I do think Nintendo will release a new 2D Mario on the Switch and that it won't be part of the "New" series (maybe wishful thinking but I really want this to happen).

Is this game good? I like 2D marios. Should I buy it?

I voted 15 - 17m.  The game has serious legs.  I defintely think it will cross the 15m mark.  If I voted wrong, then it's because my guess was too low.

I don't think we are getting a truely new 2D Mario game on the Switch.  Instead we are getting stuff like Mario Maker 2 and Super Mario 35.  These are variations on the 2D Mario theme, but I don't think we are getting a full new entry in the traditional sense.  

I think it'll end up around 12 million. I'd expect a fresh 2D Mario game (saying fresh instead of "new" to avoid any confusion, as it clearly needs to be a fresh 2D series and not continue the now tired New series) either in 2021 or 2022. They've gotta be well into development of another 2D Mario game seeing as how this one was just a quick port and it was released nearly two years ago. Didn't realize the quarterly sales were as high as they are, but still the next 2D Mario game should cut off a lot of sales for this one. Though if the next 2D Mario doesn't drop until late in 2022 this one could see 13/14 million since it will continue to sell well until it is replaced by the next game.

If you like 2D Mario you'll probably like it. It doesn't bring many new ideas to the table but is still a solid enough game.

Personally I prefer Mario Maker 2, but that's of course a matter of taste.

I wish Mario Maker 2 wasn't treated like such a joke in the Nintendo community. That game really deserved Splatoon 2 levels of success. My favorite Switch game.

Edit: I voted on the 12.9 mil max option, but it might do a little more. Also, I think a new 2D Mario is now guaranteed for Switch 2. Won't release on Switch I think though. Still hoping for a new 2D Zelda, at least. 

Yeah I thought Mario Maker 2 would be more popular than an old port of a 2D Mario series that feels very long in the tooth. I'm very surprised that Mario Maker 2 might not even hit 10 million. I don't get why it isn't more popular. Maybe less people are interested in making their own levels than I would have thought.

It's a very good game that suffered from being on Wii U and being too safe. I 100%'d it.