I am one of the few (now 4 yeses). I am prepared for the vitriol, but I will attempt to allay all the fears presented.
First, I have three kids. What about the kids? They are insured through state sponsored Medicaid. (Note: I also don't really have life insurance.) I looked it up, and when my kids would need my financial support, social security would pay out to them more than I make anyway if I die or am disabled from a debilitating illness or injury. So, they should be fine. Also mentioned, bankruptcy is not a desirable option, but an option to get out from under medical debt without losing everything else.
Next up, I didn't mind paying the tax penalty since the EIC we get for working the system the way we have ended up paying for it. So the fact that I don't have to pay the penalty this year is a nice little bonus, but not a motivating factor at all.
My wife is insured through her employer, and I could be too for roughly $1000 extra per month. Since that is an option to me and yet not realistically affordable, we fell into the ACA's family glitch. (Look it up. It's real. I and my family would not be eligible for a subsidy even though our income would make it so.) So the ACA's plan is also not totally affordable (and only good for catastrophic events anyway), especially considering the rest of my family is covered.
I'm the only one uninsured. I'm relatively young and healthy. I've done this for the past 2.5 years. And before kids and before the ACA, my wife and I went a year without health insurance because we were poor without coverage through jobs.
Lastly, while I'm not eligible for Medicaid like my kids are, I have learned through some conversations with the Medicaid people that if something were to befall me, I can turn to them for assistance (likely because I have kids). For instance, they gave me an example of a broken arm ($8000). They would likely be able to pick up the tab after $5500 on that injury. And I know in an emergency, I would be taken care of even if it might cost something later.
Look, I'm not going to champion the cause of being self-insured. I'd rather be insured. But, I'm taking a calculated risk on myself. My family medical history is pretty clean. I don't want a job just for health insurance. I want to be with my kids. (I get to be a SAHD now on which it is hard to put a dollar value.) I even implored my wife's employer (my previous employer, too) to stop offering spousal coverage. If they did that, we would qualify for ACA subsidies and all be insured.
TL;DR The problem is the ACA family glitch. Look it up. It's been written about for years. Here's one example article that sums it up pretty well.
https://www.healthinsurance.org/obamacare/no-family-left-behind-by-obamacare/