There's a variety of problems with any kind of consumption tax that's large enough to replace income taxes.
First, fraud. To completely replace income taxes, a national sales tax would likely need to be around 15% (and likely higher than that if staple foods and such are exempted). There's tremendous incentive to smuggle and work "under the table"
Second, fairness, the term "Fair Tax" notwithstanding. Inevitably, there's a call for exemptions, and no matter where you draw the line, you wind up with ridiculous situations (in Canada, a single donut gets taxed, but a package of 12 is considered a grocery item and are not). These exemptions inevitably become a political football all their own.
Flat tax doesn't work either, by the way. The middle class assumes a massive chunk of the burden.
The trouble with "personal responsibility" is that it's impossible.
Can you provide yourself with security and disaster response as well as your local fire and police departments? No? And even if it IS "yes", do you believe that everybody can?
So, there's a baseline of government service that most of us can likely agree on, so then it's just a matter of agreeing to draw the line.
Social Security is not insolvent, and does not have to become insolvent unless a given "side" deliberately wants to drive it there to prove a point. Giving seniors a baseline standard of living is a humane thing to do, and all of society benefits from it.
Education is a little trickier, but I'm pretty sure we can still all agree that there's a baseline level of literacy that society as a whole benefits from.
I don't agree with every single program and subsidy, either, but I don't want to see muscle cut along with the fat.
I think you'll have a hard time finding anyone who really likes corn subsidies, outside of corn farmers. Absolutely, the US has become addicted to them.
Farm subsidies in general require an overhaul. One that will require cooperation with a good 60 countries. If you want the US to unilaterally rescind all its subsidies, that's a wonderfully noble effort, but you'll disrupt the tens of millions of people who depend on the various crops that are supported.
Your argument suggests that the only reason that people are unable to cover medical bills is "lack of planning".
Sure, I have little sympathy for someone who insists on spending every last dime and expects the taxpayer to take care of him when he needs, but that's hardly the only reason why people fall through the cracks.
There are a couple of relatively easy things that can be done to keep SS solvent, though:
1) Raise the income cap (slightly)
2) Raise the retirement age (slightly); a way to make this one more palatable is to maybe introduce some incentive to workers who decide to postpone retirement and keep contributing to SS instead of forcing everyone.
There's a very simple purpose for entitlement programs: it's the understanding that there's a social benefit (i.e. to EVERYONE) when seniors are guaranteed a minimal standard of living.