No, that's just the way to transfer the costs back to older/sicker people, it doesn't do anything to fix the overall costs (and might drive them up by delaying care.)
The first is because the administrative costs are much higher than in other developed countries (about 25 percent). The second is because the U.S. spends much more than other developed countries for the same things (e.g., drugs, doctors, medical equipment, services). The third is because people in the U.S. receive more medical care than people do in other developed countries (for example, they're much more likely to get expensive surgeries).
A cheap, catastrophic insurance coverage plan for young, healthy people addresses all three of these reasons.
No it doesn't. This is insurance, if the young healthy people aren't paying more than a bare minimum, there isn't enough money to cover the sick. You can't mandate care must be given and allow those unlikely to get sick to barely contribute, that's not the purpose of insurance which is to spread the cost and risk across the whole pool. What you propose does nothing to solve the actual problem, providing care for those who actually need it.
No...
The way to "fix" the exorbitant cost of healthcare is to allow young and/or healthy people to sign up for the bare minimum: a dirt-cheap catastrophic plan that covers the absolute basics and prevents personal bankruptcy. Unfortunately, this hasn't been done.