Sony is doing just fine in the United States. They already have been aggressive; EA and Activision's two biggest games of the year a testament to this in terms of selling power. Sony will most likely announce a pricecut in the Paris Game Week. September is one of Sony's strongest months historically; Metal Gear Solid V: The Phantom Pain going to be a main factor. That, coupled with a possible pricecut, be it $50 or $100 off, will be more than enough for the PS4 to succeed in the United States.
If anything, and no disrespect to the OP, Sony's lead worldwide means a lot more to Sony than winning one region. Even if the biggest region is won, it will not matter much if the other regions are not as profitable.
" It has never been about acknowledgement when you achieve something. When you are acknowledged, then and only then can you achieve something. Always have your friends first to achieve your goals later." - OnlyForDisplay