Too bad the 4.5M mark was just missed by a hair
1. No game on the level of NSMBU Deluxe releases early in 2020, so Switch will have to ride 2019 releases and evergreens until Animal Crossing.
Well, there's Tokio Mirage Sessions, but that's not nearly as big as NSMBUD. However, it could help to keep the sales afloat. New shipments of Ring Fit Adventure would certainly do the trick however, considering how well it's selling and how supply constrained it is. And Luigi's Mansion 3 seems to be a big hit in Japan, too, so those two titles alone could nullify the NSMBUD/Smash early year boost from last year. And then there's Pokemon...
So yeah, I think the Switch will start growing a small gap right off the gate and then grow it a lot bigger once Animal Crossing releases.
The Nintendo eShop rating Thread: http://gamrconnect.vgchartz.com/thread.php?id=237454
The Steam/GOG key gifting thread: https://gamrconnect.vgchartz.com/thread/242024/the-steamgog-key-gifting-thread/1/