None of the maladies that you enumerate have anything to do with Training and Licensing.
Nearly all medical malpractice is the work of a dually trained and licensed physician. Most airplanes and cars that crash have licensed, if not well-trained, operators at the controls.
Enforcement is the answer but wholly impractical. It would require a million Coasties or Water Cops for just US waters.
I'm not disagreeing with you entirely, I attended more schools for training and certifications with regards to shipboard navigation, seamanship, damage control, and much, much more than I care to remember. Engineering early in my career until I figured out I might actually like to enjoy a port visit. And this was for fairly large ships. Celestial navigation, no problem here. Even used NAVSAT at the beginning of my career, the precursor to GPS.
And for the record, I did complete my boater's safety course to be legit. And I don't own a large trawler or similar as you likely do, you are living my dream. My boat is a 15' utility boat.
But I will say this, having seen and read through the message traffic for quite a few maritime mishaps, government, commercial, and private, licensing was rarely the problem.
Typically it was someone not paying attention to what they were doing, usually as a consequence of fatigue or other factors. Or in many cases, the individual or couple who want to cruise the world and end up boarded by pirates in various parts of the world.
Not maintaining a proper watch, drinking, not maintaining equipment, or navigating a new area with little local experience.
I recently read a post on another forum from a couple who want to cruise the world WITHOUT a satellite and working HF data solution, and I would not be without either on blue water.
There is also that feeling after leaving the confines of ones typical existence and getting that initial "I'm free" mentality when going out on the water.
Sometimes when you attempt to prevent something, it is in effect encouraged... The systems are already in place, but some folks just don't care, and probably should not be out there anyways...
At any rate, just my opinion. I really enjoy this forum and all the folks here!