I don't much agree with Wikipedia's classification of presidents, or with your denigration of TR as a populist. However, that's all pretty much beside the point.
The presidents named inaugurated the Federal Reserve system, the income tax, the Social Security old age and disability insurance system, Medicare and Medicaid, and universal health insurance (Obama's as-yet-incomplete work.) A lot of lesser programs were started along the way. Wilson, by giving us a banking system and a broader window for taxation, gave us the financial base without which we could not have a stable, functioning government. Roosevelt defended democracy and capitalism against the socialist alternative, and capitalism won, with his help. Johnson broke the back of institutionalized racism in this country, the first president since Lincoln to bet the farm on racial justice, and we all won. Obama, with a lot of help from G. W. Bush, saved this country from entering a second Great Depression, and has taken some steps toward fixing the problems of health care in this country. (There are two problems: health care doesn't effectively or economically reach people who aren't insured, at this point 20% of the population; and it costs 16% of our GDP.)
We live much more decently because of government than we could without these services. We are also not free to withhold all these services. Keep in mind that in 1932 things were so bad that many Americans would have desperately chosen communism or fascism had government not stepped in to prop up the economy; and had we let libertarian laissez-faire stay its hand in 2009, we would have experienced another crisis of democracy.
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