cole over greinke

Any surprised they didn't make more of a push to sign cole, vs trade for greinke? I'm assuming the trade for greinke signaled a low faith in keeping Cole. Also I get that 9 years is way longer than they like to keep folks. But per year the salary difference is minimal: 36/yr vs 34/yr...and you get a top 5 player in the league in his prime vs one that has left his prime. Unless he really did not want to be here, wouldn't it have been better to keep Cole by a country mile?