You could but without insurance, you are taking a big risk. The point is that I cannot just buy insurance that covers catastrophic stuff. It is binary. Either I buy insurance (crazy premiums) and then I might as well use it everywhere or I don't. If I don't buy insurance, good luck.

The point is that Insurance should be offered for catastrophic issues with caps and out of pocket limits and premiums should be much lower because the insurance should not cover basic stuff and for those, we should use cash thereby have price transparency AND market competition b/w various providers.