I think a lot of 20-somethings think that they'll have the same access to health insurance they get now when they're in their 30s and starting a family.
Well won't that be a surprise when they see their premiums with a partner and children. I know I was certainly surprised to find I went from paying $300/month for myself to $1300/month for a family.
I think they're going to be a lot more surprised when they let their insurance lapse for a few months and find out that the ACA amendments provide guaranteed issue only if you've had continuous coverage --- without continuous coverage, you can be uninsurable without first working a full-time job for a year.
Not "expensive to insure". Uninsurable, at any cost.
You can skip coverage for up to 3 months a year ("Short Gap" exemption). If you do this at the end of a year, you can get back in Jan 1st of the next year without penalty. You could, depending on risk level, only be insured 9 months each year to save on costs.