Yes...... as long as they dont release Mario Kart 9 anytime soon.

Maybe. I hope so. The best entry should outsell the worst entry.

Yeah, I agree with that.

Combining both versions, I definitely think it'll pull it off. MK8D is shipping 1 million copies every quarter, and that's going to be way up this quarter thanks to the holidays.

Mario Kart 8 Deluxe's shipment data per quarter: Quarter (Total)
Q1 FY 2017: 3.54 million (3.54 million)
Q2 FY 2017: +0.88 million (4.42 million)
Q3 FY 2017: +2.91 million (7.33 million)
Q4 FY 2017: +1.89 million (9.22 million)
Q1 FY 2018: +1.13 million (10.35 million)
Q2 FY 2018: +1.36 million (11.71 million)
Q3 FY 2018: +3.31 million (15.02 million)
Q4 FY 2018: +1.67 million (16.69 million)
Q1 FY 2019: +1.20 million (17.89 million)
Q2 FY 2019: +1.12 million (19.01 million)

With ~10 million units to go & the legs it has, it can ship between 4-6 million units a year and can pull it off some time in 2021.

As for the Switch version, by itself. That's going to be a much tougher task. It needs to ship another ~18.3-18.5 million units to pull it off. That's going to be extremely difficult to accomplish, even for Mario Kart. I'm going to take a "wait and see" approach for that one.

Combined it looks like it will. Switch alone is possible as well, but that’s very far away. I think if will fall short, but that wouldn’t really be ‘failing’, MKWii’s legs were (are) insane.

I'll be optimistic and say that MK8D can pull it off alone in the end unless Nintendo comes with a MK9 before 2021. And unless Nintendo brings out MK9 next year already, beating MKWii by combining Wii U and Switch numbers are already in the bag.

I mean, according to PAO's post MK8D sells about 7M a year on Switch right now. I do expect the sales to slow down a bit with time, but by end of 2021 it should sit at only 2-6 Millions from MKWii (3M this holiday season plus 5-7M per year in 2020 and 2021) unless a new one came out in between, which would drastically slow down the sales of MK8D.

It really depends on when MK9 releases. But combined I'd say yes. Just the Switch version? Leaning towards no at the moment.

Without a doubt, it has yet to become a pack in title for Switch.

Seems like the attach rate is staying in the 40-50% range. That is kind of nuts considering the game launched over 2 years ago, and is essentially just an enhanced port. The way it's selling the Switch version alone is going to pass the Wii version.

Switch+Wii U is pretty much certain. Switch-alone is possible, but we'll see.