Again, I am sympathetic to your point. And, true, some teachers who are not teaching in the first place would not want to then tutor.
And, true, some teachers who are not teaching in the first place would not want to then tutor.
Some also have other things in their lives too. I can tutor because I don't have kids and live close to the school. I couldn't tutor when I had to take a 2 hour commute to the school.