@Blickers,
Whether we label the Social security program as welfare or an insurance scheme, is an abstract (and I think meaningless) exercise that doesn't have any effect on how we pay for it and make the system work. Some level of means testing is already in the social security/ Medicare program by way of the Obamacare HealthCare law. It comes in the form of the decucted cost for Medicare part B. If you report an income over $250K/year the cost of that deduction triples, reducing the SS payment by that amount.
I don't think your insurance company analogy fits the problem. Insurance companies are required to meet actuarial and accepted accounting standards with respect to the reserve funds they hold to meet their potential obligations under the policies in force. This applies to all forms of insurance, though in some areas the standards involved vary from state to state.
Federal Social Security "insurance" doesn't involve any reserve funds. In theory there is indeed a Federally operated Social Security Trust, but it is simply filled with IOUs from the U.S. Treasury.
So far we have operated within the Trust limits, but that won't last much longer. The reasons are several (1) life expectancy has increased by 20+ years since the program was enacted in the late 1930s, and the time while benefits will be paid increased accordingly. Only very slight changes have been made to the eligibility age, so in general people are paying in to the system for about the original duration, but drawing benefits for two to three times as long as originaly envisioned. (2) the demographics of the country have changed significantly since the late 1930s. Birthrates are down, the population is older and the ratio of people paying in to the system to those drawing benefits is now much lower.
In short the system simply cannot be sustained indefinately in its present form. The obvious options are to delay the age at which one is eligible for benefits, making it more like the original program; to raise the taxes for those paying in or reduce the benefits being paid out. None of these is likely to be very popular. The alternative then is to change the system in more fundamental ways. None of them will be very popular either.
Alternatively we could keep on issuing Treasury Bonds as long as the market will take them. Our reserve currency status is already weakening in a much more multipolar economic world today, so the future of that course doesn't look good. Indeed it can end badly, as the Greeks discovered last year.