As a person who admits to not watching baseball since my kids stopped playing I wonder where does the revenue come from to sustain such contracts. Advertisers and fan attendance?
Advertising money doesn't just come from nowhere. Everyone who buys any of the advertised products pays for the advertising, including those of us who don't watch baseball.
I remember a Tank McNamara strip from long ago that dealt with the topic of enormous player salaries. The last panel depicted a woman at the supermarket, going into shock at her grocery total, and the caption was, "The buck starts here."
If MLB's only revenue came from gate receipts and pay-per-view television, players wouldn't be paid such ridiculous amounts.