But there is a minor flaw in your argument that US government spending has doubled since 1974. Sure, the dollars are constant but the population isn't. If the US population has increased about 30% since 1974, then per capita government spending has increased about 70%, not doubled. Aside form this detail, I think you're pretty much on target!

One problem with Social Security is that we can't all agree on exactly what it is, or should be. Is it a retirement plan? Welfare? Social insurance? Born in the Depression era of poverty and economic misery that very few Americans today can even fathom, it was originally intended as a form of social insurance to make sure that elderly widows, and all seniors, didn't starve. That's a perfectly laudable objective for a decent society, and one for which I wouldn't mind paying in more than I'll ever get back. But the problem is that more and more Americans came to depend on Social Security as their principal retirement income source, which was never the intention.