I was scared by #6 (being new to America and having a great plan from my former employer), but between COBRA and individual plans, I was surprised how easy it is to be covered. My COBRA was terrifyingly expensive (more than my rent), but I got a very affordable individual plan to cover myself and my spouse despite having a recent accident in my medical history. Or you could move to a country where it isn't a problem ;)
Important note, if you're not familiar with individual plans: be very diligent about reading the fine print, and (if at all possible), finding someone who has direct experience with billing large medical expenses on the plan.
Individual plans often have so many hidden loopholes and exceptions that when you actually get sick, they're totally useless. It's nasty to discover that your insurance company is going to drop you for some bureaucratic detail ("you had acne once? Oh, you didn't tell us that on the application. We're not going to cover your heart surgery.") the first time you really need the coverage.
5 shouldn't stop you. Find a problem that has been solved already and innovate on it.
Excuse Number 6: Health Insurance. I've saved enough to cover my mortgage & living expenses for a year. What I haven't saved for is an insurance plan that will not bankrupt my family if one of us has the unfortunate timing of getting in a car accident or gets cancer while I'm trying to start a business.