The majority of my professional career, I worked as an "independent contractor". So yes, I too, have some modicum of understanding. BTW, I could have avoided all that "challenge" by working as an employed for about 60% pay.
Finding customers: Easy in this case, the "Uber" website will provide the platform and visibility. That's in addition to the more traditional word-of-mouth. Let's face it, illegal cabs had existed all along, usually operating in airports. But Uber makes it possible to connect rider with drivers outside of airport. The same mechanism can work connecting skier instructors and skiers. (in my case, I worked for the same 2-3 agencies which found more work than I have time to do. I tell them I'm "off the market" when I want to take a long break -- like last winter)
Licensing: There's no such requirement at the moment. But one can join PSIA as a start.
Insurance: I don't know about ski instructing. But during my years as "independent contractors", Some of my clients REQUIRED professional insurance. Surprise, surprise, there're actually many offers out there. Just pick the one that suits!
Overhead: I have to buy my own suit.
So the equivalent for ski instructors, they need to buy their own ski jacket, perhaps have their name on it as a moving advertisement?
Yes, there were other challenges. But they are relatively easy to overcome, provided the reward is sufficient.
The question is, will the ski instructors get 40% extra pay as "independent contractors"? Or only 20%? Or 200% extra pay?