Sure, Baez is a great example of the dangers of signing a player to a big contract, but in baseball the playing field is level. What Baez started hitting like Judge while playing okay defense at SS. Suddenly his contract is a steal for the Tigers. So it's even. If Baez does poorly, as expected, or fantastic he's paid the same.
If the Tigers can't reduce what they're paying if Baez sucks, then Baez shouldn't be allowed to hold out if he out performs. If the Tigers CAN reduce what they're paying Baez then I'd advocate for Baez to be allowed to hold out for more if he excels.
Now this differs from what a lot of we're used to in our jobs, but sports jobs are different from what a lot of us are used to as well. Most of us aren't in a situation where we can't quit from our job and then have our previous employer prevent us from being able to get hired by a similar company in a different part of the country. Yes, there are non-compete clauses in some people's contracts, but those are rarer and not nearly of the same level of exclusive as NFL where it's basically: Here are the best 32 employers out there where you can make big money, or you can go to anyone from 33-whatever and make maybe 1/50th of what you'd make with the top 32.