For the record, I think Guthrie benefited greatly from being a Royal, and the Royals benefited from him too. Both sides won the contract. We have to remember how bad Royals starting pitching was in 2012. He brought stability and the consistency to pitch keeping his team in games (the record on games he started is a fluke, but it shows he didn't get rocked much until this year) and eat innings. 200 IP in 2013 and 2014 allowed the bullpen's development, and made Hoch and Davis moving to the pen possible.
You're almost never going to sign a player over 30 for a deal longer than 2 years and get value out of the end of the deal. Like mocat said, its how contracts work.