They should also care that their society remains well structured because it increases the probability that their own situation improves over the course of their life, and that their children/grandkids will be wealthy.
Are you calling USA "well structured"? Socialist European nations have much more income mobility than USA has. Few are threatened with penury, most employers pay a living wage, and many more people who have a great idea and the will to build it, do so.
Whether the US is well structured can be debated, but my point is only that even a well structured society can have poverty that cannot be eradicated in a generation.
Consider the US in 1870: per capita GDP was $3,000, so even with a totally noncorrupt and absolutely competent government, and perfect wealth inequality, the entire population would be in poverty by today's standards. Income growth takes time.
As to your point: wages in Europe are lower than in the US, and there is much less funding available for startups.
Europe is also not appreciably more socialist than the US:
Are you calling USA "well structured"? Socialist European nations have much more income mobility than USA has. Few are threatened with penury, most employers pay a living wage, and many more people who have a great idea and the will to build it, do so.