First of all, I'm not at all saying that "US should change its culture". As any advanced culture you should adapt slowly with times, and absolutely not aim to "change the culture" other than for self-betterment. All I'm saying is that you should cease pretentious bullshit about how your culture is "superior" when it's obviously superior in some areas - and drastically inferior in others. And generally unfit to most of the world because of its specific focus on selfishness, which is currently heavily taxing your society to the extreme such as general ungovernability due to pandering to special interests (see - selfishness) and inability to compromise (see - winner takes it all opposition style system over consensus).
On unemployment benefits in Europe - they are small because high taxes pay for most necessities through making them free or extremely cheap. That is, universal healthcare, free education, functional subsidised infrastructure and so on. US model is essentially "pay more and subsidise little". Nordic model is "pay less and subsidise a lot". Back when I was a student on state aid for about a year I had about 100EUR after paying for bare necessities like rent and food. But I never had to be afraid of getting sick, my education was basically free, food at university was heavily subsidised, sports activities were all but free, and so on. At the same time a US student has to take heavy loans just to pay his tuition in a high quality university, or have his family assist him. Or will have to work during his studies, unable to focus on studies alone. Same thing for unemployment benefits (which are notably low in Germany because Germany is currently a de facto full employment economy and most benefits are now in process of being moved to low income part time workers instead).
Overall, your entire argument is that of a supremacist. "We are superior, others are inferior, they should just adapt our superior system over their inferior one". You're in a good company that way. Historically, most of the worst tyrannies adopted just that particular attitude. This is a sign if inferiority complex, rather than any kind of superiority.
Now for the most ridiculous part of all. "Horrendous social, cultural and economic structures Japanese live under"? Has it ever occurred to you that to them, their lives are a norm and US social, cultural and economic structures seem horrendous? Which would be because different cultures create different expectations in people, alongside different reactions to exactly same situations. What you view as "horrendous", many of those who grew in the culture view as "great" and what you view as "great" many view as "horrendous". For example, must of current European opposition to TTIP is rooted in the fact that the deal would likely force us to relax some of the state structures related to universal healthcare and allow US style profiteering on suffering of others. Because in US the social norm is that open profiteering from suffering of those poorer is completely acceptable and even encouraged: see opposition to universal healthcare "but what if my money goes to take care of someone who I don't care about". In most of Europe it's viewed as horrendous and downright monstrous and paying taxes to help those less fortunate is viewed as a civic duty and insurance for oneself in case one ends up among those less fortunate.
Just one of many massive cultural differences that show particular inferiority of US culture's way of doing things. At the same time, one should also note the superiority in other things - such as for example being better at motivating entrepreneurship, being far more tolerant of failures (in much of Europe and Japan for example, starting a company and failing is considered a black mark on one's reputation which reduces motivation of potential entrepreneurs.) It's also notably less ethnocentric and as a result notably less inherently racist (Japan is especially bad here), tends to allow for significantly greater personal freedom in certain areas and so on.
Conclusion: one should not argue about "supremacy" of any given culture. The only thing that can judge that is history
P.S. FYI I'm a Finn (thanks for the lecture on terribleness of my culture and country in one sentence) and I'm very well travelled and knowledgeable on various cultures from my work with exchange students from six continents over the years.