On one hand, it seems like a great idea for those whose employers don't provide subsidized insurance coverage. If it's truly affordable, it should allow more people to get routine care. Especially for women, who generally need more routine doctor visits than men. OTOH the things that bankrupt people are hospitalizations and real insurance plans are generally there to help mitigate that.
How would such a model handle predictable-but-expensive medical needs, like hip replacements for the elderly and monthly prescriptions for HIV and cancer patients?
The other two are probably going to be fixed through direct market forces. If the people of America can only pay $X, then the makers of the drugs can only charge $X + small premium to have a market. Since they would face a similar price pinch abroad, they'd have to adjust their prices.
We've seen the inverse of the price pinch with the epi-pen scandal. The makers knew the price could go up since insurance would absorb the cost.