It seems that PS4 was severely underestimated and the Xbox was severely overestimated. Nintendo was just too unknown to make a realistic prediction. The Wii I predictions that were made were very much off.
After 2014 though you see a lot more realistic predictions for the PS4.
It be nice to update those predictions.
Switch-80 million by 2022
Xbox-53 million by 2022
PS4-115 million by 2022