One thing that small-market teams often prioritize is good pitching and sound defense. It is tough for teams like the Pittsburgh Pirates to retain their top hitters, but having good pitching and defense will always keep a team in it. Look at the Pittsburgh Pirates from 2013-2015, they did not have elite hitters up and down the lineup but always had a chance to win a game when they were in the field.
It really is no coincidence that the Pittsburgh Pirates have struggled the last few years and have had one of the worst-rated team defenses.