Ironically, I have known a great many professionals - doctors, for example - who don’t have a problem with providing a free service, or trading for service, or working for half-pay on the occasion.
It’s called charity, good will, giving back to the community, and it used to be a normal part of being a professional whose services are highly valued and in demand. “I have made a comfortable living off what I do; I can afford to be generous every so often as a good example to others.”
Socialism makes a sacrament of freeloading and renders true charity impossible.
I’d venture to say that virtually all docs perform free work on occasion. I’ve never met a doctor (not that that is anything but an anecdote) who went into the professional purely for the money. And I have a fair number in my family.
But that’s not a valid formula for providing healthcare to a general population. In other words, it has to be the exception, and the rare exception, given the overhead on offices, staff, malpractice insurance, supplies, and plenty of other things. Plus the general certainty that 100% of the population will need to see a doc for something at some point.
That is a profound statement. Charity is a virtue; socialism destroys virtue generally.