Why is there a ceiling on wages subject to SS & medicare withholding?

[mopinko]

17. because it is basic insurance. no more, no less.

i vehemently reject scrapping the cap, or requiring taxes that do not return the same benefits.
however, i see no reason why capital gains and dividends shouldnt also me included in the program. a lot of people relying on this income dont need the basic insurance, but many do. they should also have access to this important social insurance.

the problem is that extending it to other income, and the way that independent contractors are taxed, having to pay both halves of the premiums is a heavy burden. it is also why many independent contractors dont pay their taxes at all. 13% is a heavy lift.
i can easily see the down side of changing this, but damn. i wouldnt volunteer to pay the full boat on that if i could avoid it, either.
in the gig economy, maybe this should be revisited.