The popular line from those that wish to criticize teachers is that "Good teachers are worth their weight in gold".
Every person that says this follows it up with a list of excuses for why we should pay them in dirt.
Treat teachers like they're providing your students with an education. Treat teachers like people that are developing children into citizens. They're not being asked to peddle some wares, manufacture something, or generate more money. They're being asked to nurture and develop citizenship.
A teacher can make one child a great citizen, and in doing so they would outshine all the salesmen in the world.