About 30-40% of non-medicare America lives in non-expansion states, more if you include long-term resident undocumented (not just seasonal workers).
Medicaid is not available to 'unenemployed' people in most states in any sort of automatic way, so if you were employed in most middle class jobs, you won't qualify without serious tax shifting around the eligibility year enrollment cycle.
If you make under 133% of the federal poverty level in non-expansion states, you don't qualify for the exchanges.
Each non-expansion state's metrics for Medicaid qualification are slightly different. Unless you are under-18, a pregnant mother, or have ESRD, you probably don't qualify.
Also, to a different point above, COBRA is not 'discounted'. It temporary, but generally just as expensive as private insurance.
Kaiser Family Foundation is a great place for digestible data on US health care.