Realize first that what we are talking about is not health CARE, but health care INSURANCE offered by private for-profit companies
Now, assuming we reject universal insurance funded through tax revenue*, there are two ends of the spectrum
option 1) everyone pays the same amount, regardless of age, gender, pre-existing conditions or ice-cream preference
option 2) premiums are based entirely on personal history. Those that are older, female or in poor health pay more, sometimes astronomically so.
Personally I don't like either of these extremes - option 1 is very good if you are old, sick but wealthy, and very bad if you are young and poor. Option 1 is the epitome of the older & rich sticking it to the young and poor.
I'm not a fan of option 2 either because it leaves the old and sick out to dry, and very often those costs just get re-absorbed by family, community, and ultiamtely the system itself (at even higher costs due to late treatment). As a compassionate human I believe we have an ethical obligation to take care of the sick and less fortunate in our society.
Therefore, what we're all discussing is where on the spectrum we'd like to set health-care premiums. Boarder42 brings up a good point that income is not always the best reflection of ability to pay; total assets (or perhaps investments) might be better. Of course is you are recently retired with $1MM it might seem like you have a lot of assets, but you are counting on that to support you until you die, and I'm certain that a retiree living on $40k/year (4%!) would object to paying several times more for healthcare than someone earning $40k/year but with little savings. It's also highly de-stablizing to change health care costs so dramatically on fixed-income individuals.
Ultimately the question we need to address is where do we set these limits? Medicaid has offered a form of health care to financially needy families. Where should that threshold be? Health care for older and sicker people costs more - where should premiums be set for those individuals?
If we can focus on the questions, it might clarify our answers.