RedKing,
Your question wasn't why people wouldn't want nationalized healthcare, it was why they wouldn't choose to purchase insurance.
And even bringing it down to the minimum level, I think "unable to afford it" is a pretty good excuse.
If you want to talk more about insurance in general....
Personally, I'm completely opposed to insurance for routine procedures - it's a perverse incentive that utterly distorts the market and results in a situation that leaves everyone worse off, including the insurance companies. I think if we really want healthcare for everyone, we should nationalize it (and not just nationalize insurance either, which compounds the problem).
I think we should be able to purchase healthcare plans instead of purchasing insurance plans - I'd love to be able to just pay a pile of money each year and get a guarantee that the doctors and hospital will do their best to make me healthy because it helps their bottom line. I'd love a situation where the incentives would actually line up.
Insurance doesn't do that - in fact, it does the exact opposite. It encourages doctors to push for multiple visits, extraneous tests, and unneeded procedures with actual patient care as only a secondary concern, since patients getting better doesn't help them in the slightest (talking from an administrative and organizational standpoint here). It's impressive that hospitals put patient concerns as high as they do, honestly, but there's absolutely no incentive to keep down costs here or act in reasonably economically efficient ways.
Insurance is, and only functions well as, a safeguard against things that are unlikely to happen. Insurance for regular dental visits are perhaps the most retarded thing our country has ever invented.
Why the hell would you need insurance for regular procedures? There is no possible way adding a middleman could work out for anyone but the middleman in this sort of situation. It would be like buying insurance against an empty gas tank - for 200 dollars a month, you get as much gas as you need! (of course, you only average 80, but ignore that!)
What it means, though, is that the gas company has no incentive not to jack up their prices - after all, you don't care, you'll hop into whichever one is closest.
It means they have no incentive to work efficiently - they can just pass the costs onto your insurance company.
And the insurance company, just to stay afloat, has to pass those costs on to you.
It's a bad, bad system.