It's not my intent to bring a political tint to this conversation, but I have to believe there are two major contributors to the excessive salaries. One is collective bargaining, and the other is oneupmanship. A player has good numbers, teams want him/her, and the union and agent take over. Back in the day if a player could make a living without having a second job he was doing extremely well. All pro sports is this way, and you can't really blame the players. If someone offered me an insane amount of money to play a game I'd be a fool to turn it down. BUT, what happened, as always, entitlement mentality took over and agents and unions became involved. Had the owners pushed back instead of caving to the thought of not having a certain player there would not be a problem. But as always, someone is willing to pay for the stats.
In no way would I place any "blame" on the players (or their agents) for accepting such ridiculous salaries. I'm just saying that few, if any, of those players are deserving of such high-level pay.
As for "overpaid poster boy" Chris Davis, if ANYONE in just about ANY profession performed so poorly in his/her job, they not only wouldn't have been paid a huge salary, they would have been fired long ago. After all, Davis is still hitting under .160, and no other major-league player with a significant amount of at-bats is under .190.
Obviously, the price of most everything has ballooned big-time over the past half-century, but when the VERY BEST player in 1966 (Frank Robinson) earned only $100,000 while the VERY WORST player in 2018 is "earning" $21,118,782 yearly and more than $100,000 a game -- $130,362.85 to be exact.