I feel like this number is some kind of misunderstanding or miscommunication. As far as I’m aware there is exactly one source for it, a Japanese video games analyst who said it was stated during an investor call.
The Steam sales are estimated by all sources to be in the region of 500k, with ranges from 430k - 645.5k. So for this number to be correct then the Steam numbers need to be on the low end of the estimate, Square would have shipped zero more physical copies since day one and it sold an almost negligible number of digital copies on PS5 in almost 2 years. This all seems a little much.
The alternative being the original 3m number was wrong, which seems unlikely.







