I have read the Wiki article on the ACA several times and I confess that it remains a mystery to me. By my own rules I should be silent about this law until I understand it, but I will not be silent.
Certainly more people will be insured under an expanded Medicaid program for the poor and working poor. That is a good thing but it will be entirely an expense and without balancing revenue other than projected reductions in the growth of Medicare for the bourgeoisie. Those reductions explain much of the hostility toward the ACA among the Middle Class.
People who make more money than those eligible for Medicaid will be required to buy or continue to buy health insurance. If they do not they will be subject to fines (taxes in John Roberts opinion). these fines will grow each year until they are really painful. Many people so affected have long held health insurance. Many of these are now being told by insurance companies that their existing policies do not meet standards set in the ACA and will be cancelled. At the same time these insurance companies are offering these people policies that meet ACA standards but are much more expensive.
An example. A man who lives in Rappahannock County runs a landscaping company. His brother works for him. He has a wife and two high school age sons. He is not a wealthy man. He does work for us at our house in Alexandria. He told me the other day that his presently held insurance costs him $500/month for family coverage. His insurance is being cancelled for the reason given above and he is offered an ACA fiendly policy that would cost him $1200/month. Would he be eligible for a federal subsidy? I don't know but I doubt it.
Perhaps there are other people who will be offered cheaper health insurance without subsidies.
I don't know. Inform me. pl