Your arguments are spurious. I provided a legal precedent where the "general welfare" clause in the pre-amble had been used to support the government doing something in the public interest.
I don't personally think that the healthcare reform bill passed by Congress was actual reform, but I also don't think it was unconstitutional. Yes, it helps that insurance companies are no longer allowed to refuse coverage for pre-existing conditions or, presumably, to charge people with pre-existing conditions so much for coverage that they can't afford it, but it still doesn't address the problem of a for-profit, predatory insurance industry, either.