I have to challenge this! If something (talent, buggy whips, whatever) is scarce, and it's being priced in an auction market...pretty much by definition, it's not "overpriced." 
That's the economics of it. In a less purely micro-economic sense - factoring in any kind of social value/social good, etc., yes, Trea Turner's contract is overpriced. All major league contracts are overpriced. A mediocre, bit-part entertainer earns ten to one hundred times as much as a school teacher?
Or maybe they're not; maybe our society really does value passive entertainment (whether sports, movies, whatever) that much more highly than... well, pretty much anything else. How many people do you know who routinely pay $150/month for cable and/or streaming TV, but who would freak out if their property (school) taxes were increased by $1,800/year, to support higher teacher salaries? What do we really value?