I ran my own small business, provided great healthcare for myself and a couple of employees, and managed to have good healthcare after I shut the company down and was unemployed for a while. I had to do a little research and make a couple good decisions, then it wasn't an issue. And that was before the Affordable Care Act, which provides free healthcare in many states for people who can't afford it.
Well, in my state the individual market is tied to the state healthcare marketplace, and all of these are PPOs. At the worst, you'll pay $1200 a month for a plan whereby you have to stick to a finite network, and get approval every time from the primary care provider. And there's still a several thousand-dollar deductible. Even if I chose to offer $2000 a month for a plan that's a more open one, there's nowhere to give that money to someone.
I consider that a barrier to innovation / entrepreneurship because many people don't want to quit cushy jobs as employees for a situation like that.