I honestly think that releasing in 10 more countries means that PS4 isn't able to meet demand in the US.
It could sell more if more units were available. Better supply as well as a more steady demand for PS4 I think will leading it to outsell the XB1 on a regular basis.
The early adopters are the fans who buy a specific console regardless of specs and price of the competition but there are just so many Xbox/Halo fans (7-15 mill). :p just teasing
In any case the current and growing PS4 (34%) market share in the US is a huge improvement from PS3 (23,6%).
PS3 (28.25 mill) vs. XB360 (46.29) vs. Wii (45.16)
PS4 (2.19 mill) vs XB1 (2) vs. WiiU (2.25)
Titles that will keep the PS4 selling loads in the US (and here in the UK as we like our action too):
Infamous SS
The Order: 1886
Uncharted 4
God of War 4 (Norse mythology with new protagonist)
Santa Monica's WRPG
Guerrilla Games' new IP
London Studio's new action IP
etc.
