1) I think market forces had a >lot< more to do with the better pay of US blue collar workers after WW-II than the factors you cite. We were the only industrial economy left standing after the war, there was a world of pent-up demand for products, and a finite number of US workers available. So, these workers could demand historically high wages. And that same market force enabled them to have powerful unions. It was a momentary aberration brought about by WW II, and it ain't coming back.
2) US workers are now (properly) facing competition from foreign workers, and it is driving US wages down, but on the whole there is more "good" being done because the wages going to foreign workers are making a >huge< difference in the quality of their lives. A hundred dollars paid to a poor guy in Cambodia buys food for his family for months, the same amount paid to a worker in a developed country buys one nice family dinner at a restaurant. Where is the best marginal utility/happiness-per-dollar?
3) Improvements on some of these things could be a start: U.S. public schools, especially in poor neighborhoods, are not very inspiring (though the sums spent on them are). I'd say a 21st century equivalent to public libraries would be government programs to enhance internet access (though there will be 1 million cat videos and porn clips for every instance of someone downloading a copy of "Tale of Two Cities").
4) When we talk about helping the poor, I think we march off in the wrong direction (and implement some bad "solutions") if we don't ask hard questions first about the causes of poverty in the US. We have cultural issues that need to be talked about, and we need government policies that at least don't exacerbate the cultural factors that lead to poverty.
From
the LA Times:
Now, even if more people avoid poverty or get into the middle class, that doesn't necessarily address the issue of income inequality (because "middle income" is a relative term).
5) But if US workers bring skills and a conscientious attitude toward their jobs, I think they can be more productive than workers anywhere.
6) And productivity is a necessary (but not sufficient) condition for increased pay.