not sure how many young adults don't care about insurance but if it's only 5% of uninsured 18-24 yr olds, then there are still > 1 million young adults who choose not to have health insurance.
FWIW: the Senate's healthcare bill sets 26 yrs as the limit for being considered a dependent on a parent's health insurance. Wondering if employer provided plans will be forced to carry those 'elderly' dependents?