That plan works until it suddenly doesn't. When it doesn't it's catastrophic for your finances and your health.

If you have an extra couple million dollars above and beyond your regular retirement fund you could self-insure your medical costs. But then you could just buy the health insurance.

Medical expenses are less expensive when you don't have insurance. Insurance is just for catastrophic events, if you do some regular risk analysis you can come to a balance that works for you. If you know a major medical expense is imminent then get the insurance. Most procedures don't happen immediately anyway.