I think it is he is 33 and most likely his best years behind him.27 is peak seasons for most players, he is 6 years past that.Very few teams are willing to play veterans these days that play at replacement level output.Teams are changing how they build teams and vets are getting squeezed out, even if they can put up MLB quality numbers.If they can get same output or close to it for cheaper the teams are doing that.
Plus, he's not as versatile on the field as some would want from a backup/bench player. Dozier can really only play 2nd or DH/pinch hitter ... it's not enough anymore. As you said, teams are being built differently these days.