But that's just it, people can't decide the risk because they don't know. One is aware of the cost should their car be totalled in an accident but how many people know the cost of a heart attack? Furthermore, if genetic testing was perfected and one was told they had a 20% chance of developing a certain illnes then, at least, they would have an idea of the risk.
All your suggestions would lower cost but we come back to how does one choose coverage without sufficient knowledge of their body? An analogy would be considering fire insurance without knowing if oil lamps and candles are used rather than electric lights? Fire insurance on a home heated with a wood stove/fireplace as opposed to electric heat is more expensive because there is a greater risk of fire.
Then we have young people who believe they're invincible which is one reason family insurance now covers them.
Finally, we have to remember there are countries with medical plans which complain when the cost rises from 9% to 10% gdp while other countries complain when it increases from 8% to 9% gdp all the while the US cost is 16% gdp. The point being all the news from countries whining about government medical costs should be taken with a few grains of salt.