This won’t end well. Say someone is trapped in a car and they want payment before they will come? That will diminish the people’s high regard they presently have for firefighters if they are just another money hound government agency. People already pay for the fire department with their taxes. The reason fire departments became emergency medical providers was because fires were not frequent enough to keep them busy. Now they have more things to do that make them heroes for many people but the money grab will have them risk losing that respect.
The Denver model is the best. Emergency medical care is available to all at no cost. An ambulance is always near and response times are great. When they need money Denver has lots of wealthy people happy to donate needed funds. The Denver General Hospital is one the good things about Denver, which is otherwise becoming a pretty crummy place to live.