If your healthcare is tied to your job in the USA, wouldn't that impede social mobility? If you can't change jobs because you would lose cover, how are you meant to move around?
Not saying it's not possible to move somewhere sight unseen and without health insurance (since that's presumably what older generations did) but it's still much higher risk than staying put.
There are things like COBRA (http://www.dol.gov/ebsa/faqs/faq-consumer-cobra.html) that help to bridge the gap in coverage.