Looking at how UC4 failed to break 1 million after a few weeks in NA in comparison to the game doing 2.7 million first week WW, it does show that Sony have little reliance on the region. Even worst case scenario, UC4 will have passed 3 million WW and that's low balling for the month, but it means that NA possibly accounted for about a third of UC4 sales. Sony should thank the stars that the Playstation brand is a genuine powerhouse in EU, it's pulling in some serious numbers. Digital is not announced for and I'm in the UK but purchased it from Canada PSN, however I seriously doubt digital accounted for a huge chunk of the sales.
No idea how other upcoming first party games will do in NA though, from the games announced I can only see Horizon doing half decent and the inevitable GOW4 will do well. But GT Sport, GR2, TLG, Detroit etc ain't going to move the needle even a tiny bit in NA, will be another case of EU doing the leg work