It has a 3m lead over it's main competitor which has had a myriad of problems since launch from marketing, to pricing and software.
I'd hardly consider it dominating consider all the cards landed in their favour. In fact it's a region Sony definitely need to push the system harder in and create more appeal for their product. Stronger competition from Xbox (and Nintendo) next time around will most likely see them losing their lead.
MS literally handed them the market on a silver platter and the PS4 isn't even that far ahead of the XBO.