The conundrum is that anyone who can afford to shell out $500+ a month for the most basic plan doesn't need it / probably has a better plan through work. The complexity and cost of the band aid system we have now is a joke the world over.
No, they can't. When I was poor and working full-time for $15/hr the best I could get was a bare minimum healthcare plan that would have taken more than the free money I had after rent and food for the month -- and this was despite not paying any cost for transportation to work and not owning a car or buying anything besides rent, food and the cheapest MVNO phone plan I could find.
I didn't live in a high CoL area either. Everyone who isn't wealthy or socially connected to get a job that pays above average is priced out of visiting a doctor at all right now.
In many states right now, there are zero cost premiums for those who make within 200-250% of the Federal Poverty Line. Percentage varies between states, or sometimes even by counties. This was part of Biden's stimulus package and should help a lot of people.