It's a waste in hindsight, and this highlights the payoff vs. risk of making such moves if you consider this. If the Sox decided to open up their wallets and offer the best pitcher on the market... market-setting money just one year earlier, they would have (maybe, dream with me) Max Scherzer instead. Up until those two points in their career, in Which Price signed with Boston and Scherzer signed with Washington, both really good and you could have an argument over which one was better. But since then Scherzer actually got better and has pitched twice as many innings as Price. That's kind of crazy to think about, up until that point in their careers you could make an argument that Price was better.
Devers could easily be MVP caliber for the next 10 years, or just a few years and fall off a cliff. But that's kind of the reality of every good player, what they do in their 30's defines their career. It can be the difference between Nomar or Jeter.