As I said, it's a complicated discussion. High entry bar, granted, does mean something, but it doesn't always mean great wages (I have a masters from an ivy in writing -- lotta good it does me!). Again, supply / demand. In a sense it's a moral issue that has economic repercussions.
Society rewards the right kind of people (smart, dedicated -- and also interested in or gifted in a valued profession). That's sensible. On the other hand, just because you're not the right kind of person doesn't mean you shouldn't make a living, and it doesn't mean the country won't be better off as a whole. By "living," BTW, I don't mean cardiac surgeon-grade living -- but I do mean enough to support a middle class lifestyle, with some economy-boosting purchase power, too.
Yes, as long as we work with the "law" of supply and demand, instructors will continue to get poor wages, just as adjuncts are paid poorly by universities. Unions are designed to circumvent that "law." That sounds artificial, because supply and demand is held to be a natural law -- but it's a pretty natural behavior for humans to band together to protect themselves.
It's all about having marketable skills. My 1st ambition was to be a HS teacher and coach but it didn't take long for me to recognize how poorly paid they are compared to the hours they work. I went the business school and CPA route snd make a very good living and probably have more coaching flexibilty and resources than any HS coach.
Would I like to work in a HS and get summers off? No question, but summers off isn't worth $100k+ or more. In a free market economy, it doesn't equate to make big wages with jobs that are easy to fill.