This is because too many places do not treat instructors as professionals. As long as they count on perks to supply them with people who are in it for the pass and don't care about the teaching, everyone suffers. PSIA would better serve its members if it was much more of an advocacy organization IMHO than a certification organization.I would totally welcome a model like in Europe. Most instructors have no idea how to promote themselves or build their brand. Half are total burn-outs who show up, draw their breathe, and draw their paycheck.
In my many years of skiing and working in an adaptive program, I have known and learned from many amazing dedicated professionals who love their work and take the art of teaching seriously. I have also seen many g-d awful disasters like those you mention...to the point of being dangerous liabilities to even major resorts. Unfortunately, most of those people are assigned to the new skiers or lower end kid classes which drives people away from the sport. And the admin too often just don't care.