Because there are a lot more teachers than lawyers. Lawyers, doctors and some other professionals make up an elite class that tend to get paid way more than most folks. People sometimes wonder why we pay lawyers more than teachers. There are a lot more teachers than lawyers so we couldn't afford to pay all the teachers as much as we pay the lawyers. Maybe we pay the lawyers too much.
Also, when you think about it, there are too many lawyers. There are too many lawyers, but still not as many lawyers as there are teachers. We need more teachers than lawyers. Teachers are more of a "bulk" class. It's just a numbers game. Hard to be considered "elite" when you're a fairly large percent of the population.
Here in Bellingham, our largest employers are Western Washington University, Bellingham school district and Saint Joe's hospital; possibly not in that order. Two of our largest 3 employers are educational institutions. Other metropolitan areas tend to have somewhat different demographics, but educational institutions are often a big share of the economic base.
There are elite folks in the economic system that it could be argued make too much money. Corporate CEOs for instance and of course those pesky lawyers. As for the rest of the masses, including teachers, we can't all be close to the top. Life can still be of quality, but we all can't be "top dogs." I once saw this quote on someone's profile that said, "even if you win the rat race, you're still a rat."
I consider myself a Democrat, but I can still remember a concept that former President Gerald Ford, a Republican, illustrated in one of his speeches about inflation back in the 1970s. Ford said, inflation was like a football game where everyone is sitting comfortably in the stands until a few folks stand up to get a better view. When they stand up, it starts blocking the view of other folks who now have to stand up to see over the heads of the first folks who stood up. Pretty soon everyone is standing up to see and no one has a better view than they did when everyone was sitting down.
Even with these thoughts, I still don't see any reason to take away collective bargaining rights. That's a different topic.
On the other hand, the majority of people in our economy aren't unionized.
Even if one has collective bargaining, there's little to bargain for when budgets are tight.
Now, I just got to thinking, if population growth was slower and there were less kids, there wouldn't have to be as many teachers. With less teachers, we could afford to pay them more. Their profession would be more of a rare elite.