I had childhood cancer and at the time it'd have costs millions without insurance.
While the healthcare market is hopeless opaque and corrupt and no doubt that does drive costs somewhat (or a lot), and probably there are things to do about it, but I think fundamentally the success of complex and expensive treatments is also driving costs - things that you'd have gotten painkillers and left to die even in '50s and '60s now can be cured/improved/fixed, it's just ridiculously expensive compared to popping some pills and expiring. Or look at prosthetics. There was a time you might have made do with crutches or a peg leg and now there are specially designed, fitted, and crafted prosthetics for various activities... that don't come cheap. Not to mention improvements to the standard of care or the sheer man-power requirements of health-care. A normal doctor's visit requires interaction with 3+ employees, across ~45 minutes, all of whom are presumably being payed more than $10 an hour, and possibly a lot more. It may actually be reasonable that budgeting $5k/person/year for healthcare is sane in terms of both risk and what you get, but just far more than people are used to thinking about or seems intuitively reasonable.