The answer, again, occurs when we think on the margin. Yes, if society had to choose in one fell swoop between ALL teachers and ALL professional baseball players, most people (presumably!) would choose the teachers as more important. But that’s not the actual decision anybody faces. In the market economy, the choice is always about paying a particular salary to this particular person. And just as diamonds are scarcer (all things considered) than water, so too are professional baseball pitchers scarcer than 7th grade math teachers.