Sorry, this is long.
Here (I personally have experience with Quebec and Ontario) the insurance fees come out of taxes. So you never see your insurance fees being paid. Ontario does have a tax surcharge for very high income earners. And yes, we know it is not free, we know we are paying for it. The point is that it is universal, we all have access (provided one is a resident with enough days per year actually living in the province - snowbirds need to be careful). And provinces generally honour each others health programs.
Yes older people may use it more, but we have been paying for it for a very long time. Younger people can have issues, they are not immune.
I just look around my circle of acquaintances and am so glad they never had to worry about their health insurance when they had: kidney transplant (in their 20s), double lung transplant, gall bladder turned into pancreatitis turned into blood clots and a 3 day stay in the ICU, flesh-eating disease in the abdomen (67% mortality rate, this person survived), emergency surgery for ectopic pregnancy, cataract surgery, plus lots of knee and hip replacements, and gall bladders out (no-one talks about it, but I know so many people with no gall bladder).
Because there is no insurance penalty, people go to their GP or a walk-in clinic or their pharmacy (pharmacists have some leeway about minor prescriptions) if they are sick, so things don't get out of hand. We don't have all the home remedies that Americans seem to depend on.
Because the province is the buyer, material costs are kept down. Billing is simplified. Clinics are private, they just bill the province instead of a private company. We all take our OHIP cards with us when we go to the doctor, or for lab tests/xrays/whatever, and it is covered.
Most vaccinations are covered, but not all - childhood ones definitely, adult ones based on need - so shingles vaccine after a certain age, same with pneumonia. Here seniors in group living get free RSV vaccine, I don't - a year too young and living on my own. So I will be checking my private insurance to see if they cover it. If you need hepatitis vaccination for a vacation you will pay for it.
There are limitation - OHIP will pay for testing blood vitamin D levels if the person has osteopenia/osteoporosis. If not, they won't pay. But they pay for bone mineral density scans.
A provincial system also means more public health - when I lived in a rural area our local health unit subsidized rabies vaccination for dogs and cats.
We still have private insurance - it may cover drugs that our provincial insurance doesn't, it may cover a private hospital room instead of sharing a room with someone, it may cover dental/physiotherapy/other not quite medical things.
The thing is, health insurance is not usually a factor in choosing one job over another, because most of our health care is covered.
Mind you, Metalcat is totally correct about provincial governments messing around in the ways she describes. I see it mostly in more rural areas, where hospitals are further apart and specialists are less likely to practice. I know when a friend in Eastern Ontario broke her leg badly, the local hospital immediately transferred her to a hospital in Ottawa that could do a better job. She went back to the local hospital once her physiotherapy needs were less. But there was no issue with her moving from one hospital to another, the doctors decided where she would be best served. Same for my other friend who was in a head-on collision (literally a Florida man in a pickup truck) - months in hospital, including several weeks in a coma, then more months of physiotherapy, then more months of home physiotherapy visits. OHIP covered almost all, his car insurance covered the rest.
And I know some of the European countries do it better than we do. We just look good because our easiest comparison is so bad