This is like claiming that because the U.S. achieved a 7.4 on a 10 point scale while some other countries achieved a 7.6 (and the rest 7.3's and 7.2's) we're somehow deficient. Roll the die again with another set of tested adults and watch the U.S. get a 7.7 and those 7.6's drop to 7.5's.
This is propaganda pure and simple. As for actual, scientific results it does nothing but repeat what we've known for 30 years going - very homogenous societies (Japan and Finland) do a better job of educating their citizens. The rest of the diversified world does an identical, mostly adequate job.
The problem isn't a skills gap, it's a jobs gap - there are no jobs. http://www.nytimes.com/2013/10/08/us/us-adults-fare-poorly-in-a-study-of-skills.html