1. The Economist is a British "newspaper" (as its authors like to call it), meaning claims of American propagandization don't make a lot of sense -- if you ever read it, you will come across subtle digs at America's (perceived) fatness, religiosity, and sometimes outright backwardness.
2. The calculations include economic projections to 2030; as we all ought to know by now, such projections are wrong approximately 100% of the time.
3. Attempting to objectify a notion such as 'life satisfaction' may be fun, but it is unscientific and not much knowledge is gained by the exercise. (As far as I can tell, the only interesting fact garnered from this exercise in particular is that two-thirds of the variation in subjective reports of well-being can be accounted for by per capita GDP.)