VAMatt on 12 January 2021
Assuming that they'll be able to produce enough units to meet demand (which we know is not the case, because I cant go buy one at retail today), I'd figure on slightly more units than the PS4 sold in the first year. So, maybe 16mm or so. However, since they cant produce enough units, I'm thinking it'll end up right around the PS4's numbers. Of course, if supply troubles continue throughout the year, it'll be lower. They can't sell units that don't exist.
