Honestly? Those most in a position to fix the "problem" have healthcare. As selfish as it may sound, i'm too happy with the system to riot. i'm in a situation where my company pays a sizeable portion of my ppo plan (i think i pay thirty bucks a month out of my pay, pre tax). If i get sick/hurt, i go to a doctor/hospital. I don't know anyone without health insurance; if my friends get sick/hurt, they go to a doctor/hospital. I believe this is the issue with the majority of americans-- most americans are insured. If you're a student, your university pays health insurance and adds the remainder to your tuition. If you're employed, your job (in most cases) also subsidizes your insurance. If you're unemployed, you get medicare. I don't really get how people can go about not having health insurance in the us. Working at a supermarket gets you health benefits for christ's sake...
The reason healthcare costs so much here is, obviously, because our system was set up to nurture the best possible medical environment. Scroll up to maddyfish's post, and you'll see what can potentially happen when socialist healthcare is implemented.
The reason no one's rioting is, there's not really a reason to.

It does.
*ed: Apparently, some don't. My girlfriend's does, however. Look into Blue Cross/Blue Shield, if you have the option.