The concern is that when people perceive the cost of government to be cheaper than it really is, they will demand ever more government benefits because they either don’t feel the cost directly or believe that others will be paying those costs.”
Social Security taxes are set at about the right level - the reason we have a problem with the program is that we spent the "trust fund" ages ago on everything but Social Security. But Medicare is a different story. Medicare taxes cover just a third of the benefits a participant can expect to eventually receive. Of course everyone thinks it's a great deal, it's like they are buying Mercedes sedans for $15,000.
Update: I know there are people who are horrified I would suggest raising a tax, that we should work the spending side or eliminate the program all together or replace it with a hybrid voucher system. I would like to see any and all of that. But there is absolutely no momentum for doing so. Even Paul Ryan only fiddles around the edges in a barely meaningful way, and he is labelled as one step away from Hitler for doing so.
If the government is going to offer an "insurance" program, then the "premiums" need to be priced correctly. If those "premiums" rise to absurd levels because the government is incompetent at management, then we might have some pressure to replace the program with something else.
If the post office were still charging 15 cents for a stamp, and then burying the resulting deficits in the budget somewhere, there would be a hell of a lot less pressure for reform.