Consider that for many generations, possibly from the time that the Constitution was ratified, parents have not been making sure that their children are being taught about the federal government's constitutionally limited powers, the power to regulate, tax and spend for intrastate public healthcare purposes not one of the fed's delegated powers.
As a consequence of epidemic ignorance of the federal government's constitutionally limited powers by FDR's time, voters simply did not question that the states had never granted the feds, expressly via the Constitution, the specific powers to establish many of FDR's "New Deal" federal spending programs that he encouraged Congress to establish.
But given FDR's popularity, I don't understand why he didn't encourage Congress to propose appropriate amendments to the Constitution to the states for his programs. Then, given that the states had chosen to ratify FDR's amendments, Congress would have had the constitutional authority that it needed to establish FDR's government spending programs.
Instead, FDR made a fool of himself with his plan to increase the number of justices as if he didn't understand the Constitution's amendment process.
Regarding what judges and lawmakers would say about the constitutionally of Medicare, please consider the following. The basic reason, imo, that post-FDR, institutionally indoctrinated judges and federal lawmakers would say that Medicare is constitutional is likely because they are as clueless or indifferent about the federal government's constitutionally limited powers as presidents who appointed them and the voters who elected them are. I suspect that, unless they lurk in FR, they have never seen the excerpts from Supreme Court case opinions that were previously posted.
Also, note that many corrupt federal lawmakers probably ran for office just so that they could fill their pockets with their "fair share" of the tsunami of constitutionally indefensible taxes that are going to DC. Here's the relevant excerpt from Gibbons v. Ogden again.
“Congress is not empowered to tax for those purposes which are within the exclusive province of the States.” —Justice John Marshall, Gibbons v. Ogden, 1824.
You quote Justice Marshall in Gibbons:
“Congress is not empowered to tax for those purposes which are within the exclusive province of the States.”
Who can disagree with that?
In Mcculloch v. Maryland, Chief Justice Marshall held that the federal government had the power to create a national bank. Where is that in the constitution?
Marshall agreed that the federal government is "one of enumerated powers." Marshall then acknowledged that "[a]mong the enumerated powers, we do not find that of establishing a bank or creating a corporation." Shouldn't that be the end of the matter? Nope:
"Among the enumerated powers, we do not find that of establishing a bank or creating a corporation. But there is no phrase in the instrument which, like the Articles of Confederation, excludes incidental or implied powers and which requires that everything granted shall be expressly and minutely described. Even the 10th Amendment, which was framed for the purpose of quieting the excessive jealousies which had been excited, omits the word "expressly," and declares only that the powers "not delegated to the United States, nor prohibited to the States, are reserved to the States or to the people," thus leaving the question whether the particular power which may become the subject of contest has been delegated to the one Government, or prohibited to the other, to depend on a fair construction of the whole instrument. The men who drew and adopted this amendment had experienced the embarrassments resulting from the insertion of this word in the Articles of Confederation, and probably omitted it to avoid those embarrassments. A Constitution, to contain an accurate detail of all the subdivisions of which its great powers will admit, and of all the means by which they may be carried into execution, would partake of the prolixity of a legal code, and could scarcely be embraced by the human mind. It would probably never be understood by the public. Its nature, therefore, requires that only its great outlines should be marked, its important objects designated, and the minor ingredients which compose those objects be deduced from the nature of the objects themselves. That this idea was entertained by the framers of the American Constitution is not only to be inferred from the nature of the instrument, but from the language. Why else were some of the limitations found in the 9th section of the 1st article introduced? It is also in some degree warranted by their having omitted to use any restrictive term which might prevent its receiving a fair and just interpretation. In considering this question, then, we must never forget that it is a Constitution we are expounding."
I'll let you read the whole opinion for yourself. Marshall is really just regurgitating similar arguments that were made by Secretary of the Treasury Hamilton in opposition to the objections of Secretary of State Jefferson during the Washington administration. (BTW, Washington sided with Hamilton on the U.S. Bank.)
The legitimacy of implied federal powers under our constitution concerns an argument that people began having during the Washington administration in the 1790's. You and I seem to agree with Jefferson that the use of implied powers will mean that there are no real limits on federal power. FDR (and just about everyone else now it seems) tends to agree with Hamilton, Washington and Marshall.
So, you and I are a bit behind in this game. ;-)