You guys are working with today’s $1.5K, extended through 20 years to get to $600K in 2030 dollars. You need to start by putting away the cost of premium from 1990. There is just no way the combined premiums since 1990 sitting in a vehicle available to general public would lead to $700K in today’s dollars.
Most people will not spend that kind of money on medical services until after they reach medicare age. Or die in a car accident. Otherwise no insurer would make profit.
Having insurance does make you cost-agnostic. When I need to see the doctor my only concern is scheduling. I don’t want to spend 2+ hours on a 5-minute session. I am aware of the cost, but I don’t care about it.