Being frugal is not the same thing as being poor, and I'm not sure why so many of the responses are equating the two.
We are NOT exactly frugal, but we have been moving that way for a few years. The reason we are doing so is so we will have the funds to pay our own way INSTEAD of begging and/or borrowing when we face a crisis. My son got pneumonia and was hospitalized for five days a couple of years ago, running up medical bills of over 10,000. We paid it. I think that is the responsible thing to do.
PS After writing the above, I saw that you were specifically talking about "extreme frugality", which I assume refers to Jacob Fisker's Early Retirement Extreme. I will note that he specifically mentions having a health insurance plan, PLUS liability insurance:
Early Retirement Extreme Day 13: Insurance
Obamacare managed to make the insurance industry even worse, in that the high deductible plans he recommends have been pretty much phased out, because they "weren't good enough".