Not sure if you are joking. Having everyone inside the pool makes up for members with chronical illnesses and other illnesses that need a lot of care. Some still healthy young poeple pay maybe a little bit more but everyone can be treated reasonably well. If you run an insurance without mandatory participation people with problematic illnesses are a risky for the business and that is one reason why the op can't get an insurance in the USA.
I think the point retillit is trying to make is, why even bother with private insurance companies if insurance is compulsory? Which is a good question.
The answer, I think, is partially politics, but also partly whether you think the competition a system like this (in theory) encourages outweighs the cost of profits.
