Game stats numbers in the initial months have been near to sales number released
Stream spy number look off as ever announced 2mil 2 days back
3 mil in 2 days is impossible
I doubt the numbers are real time. It takes time for them to be updated. Depending on the updates, it could have been more than three days for the numbers to tick up. Same for the announcement. Was it 2 million a few days before it was released when the announcement was being worked on, or when they actually released it?
It did officially sell 2 million in less than 6 days. And it seems, given by the concurrent numbers, that sales have been growing, not slowing down.
My only take is that the Steamspy numbers don't seem to be super off. I wouldn't be surprised if Steam is close to that estimated 5 million figure.
I also don't doubt that OP's estimate is far off either. It's just funny that it's the same methodology but somehow one is defacto more accurate than the other.