I just went to esurance.com and got a quote for a hypothetical family of 4, 40 yo man, 37 yo woman, 2 children aged 6 and 4.
A high deductible ($3,500), 20% co-insurance, $6,000 annual out-of-pocket maximum (does not include deductible) plan from Blue Cross and Blue Shield is $6,768 a year for someone in my zip code (Chicago). That's a pretty crappy plan IMHO, and would be stretching the affordability limit for a household in the $40,000-$50,000 income range you cited as one which should be able to afford insurance. Bear in mind that a typical 3BR apartment in Chicago goes for $1,200/month, and that won't be in a great area.
A similar plan from the same provider with a $500 deductible will cost $13,652/year.
Get one with 0% coinsurance and you'll pay $17,100/year.
How many of these are really affordable for the family in the $40,000-$50,000 income range? The one with the affordable premium would likely bankrupt them if they ever had an expensive disease in which they'd have to cover the deductibles and coinsurance and out-of-pocket expenses. The plans with more coverage that wouldn't bankrupt them if they were unfortunate enough to need it have premiums they couldn't afford.
It could be worse, if I lived in Albany NY I'd be limited to 2 insurance companies, GHI and Empire. The GHI PPO plan would cost $15,321/year while the Empire HMO plan would cost an eye-popping $31,582/year. Now, there's an indemnity plan that costs just $4,273/year but as far as I can tell it doesn't actually cover anything, just gets you a discount???