Well, I'm pretty sure the people living off subsistence farming in Europe during the Middle Ages were mostly content with their lives too (at least during peace

Well, I'm pretty sure the people living off subsistence farming in Europe during the Middle Ages were mostly content with their lives too (at least during peacetime), despite much worse education and health care than the modern Bhutanese are getting. The difference is that this was simply their way of life and they didn't have any alternatives. "Contentment" means being content with what you have - no matter if it's because you consciously decide that it's enough for you or because you simply don't know any better.