It works in Japan, which has 130 million people. They are huge.
Japan is a very homogenous population in terms of ethnicity and cultural background. In terms of political decisions, this means that everyone has pretty much the same cultural baggage and outlook on things. Chance's are that the Japanese people from opposite ends of the country are still very similar, and face a lot of the same issues, and share most of the same history. So it's probably a lot easier and faster for the 130 million homogenous Japaneses (or even the nordic countries like Sweden) to agree to do something. As oppossed to 300 million Americans who are being indoctrinated to not agree on anything.
By contrast, the US is even bigger, in both land and population, and we have quite a few ethnicities and geographic divisions. It's not unusual for say... a white person of French descent in Maine to have a very different outlook from a person of Cuban descent in Miami. And both of them might feel very different from a black person from Southern California. And a Native American guy in Oregon might feel different about things than any of the other three. And all four are going to carry different ethnic, geographic and cultural baggage. Americans in general have this perception that the only time it is appropriate to get everyone to work together on a serious problem is when there's a war. Otherwise, its often "Fuck off, I've got mine, you're on your own." It's easier to maintain support for government services if you don't have the problem of some people whining and grousing about paying taxes to pay for benefits used by "those" people.
The problem with this countries policies regarding social programs such as healthcare, and education... it simply comes down to US vs THEM. Why should I help the rural farmers, when I live in a metropolis? Why should I help the urban dense folks, when I live in the country? Why should I help the people of California when I live in Kentucky? Why should I help the poor, when I am rich? Why should I help the impregnated, when I don't have or want kids? In the USA, it's the cult of individualism. If you can't do completely for yourself, you don't deserve help.
Everything that might help you outside of yourself or your family or philanthropy..is a handout. And you should turn to the church for handouts, or go beg in the street. And if you beg in the street, for god's sake stay out of my sight. Your misfortune annoys me. Listen to some of these people that call into talk shows, bitching about tax dollars paying for poor kids school lunches.
Also, in the US so many people are so infatuated by wealth and power. And the wealthy and powerful have created this hyped-up bullshit Ayn Rand inspired narrative that their hard work and ingenuity justify their controlling such a disproportionate amount of wealth. If you aren't rich, it's probably because you are lazy, stupid or took some "loser job" like school teacher or social worker. Ethnic diversity within the population isn't the main issue, but it's an issue IMHO, ethnic diversity creates negative attitudes towards socialized services because minority ethic groups are viewed as "others". People who came from somewhere else to take advantage of American society. Fine if they want to compete in the marketplace. Not so ok if they are receiving benefits that the "locals" have to pay for.
Sadly..I see a hard sell in the US towards socialized services such as healthcare and education in the near future. I could be wrong, but we can't agree on shit..