The same reason Gilbert Gottfried continues to get work - he brings something to the table. It may not be what you particularly like or want but he does bring something to the table.
Exactly what did he bring to the table besides his ample mouth?
It's not enough to be opinionated as an analyst. You you have to be articulate, analytical, insightful, thoughtful, and knowledgable. He was NONE of those.
As far as I can tell, the only thing people liked about him is that he ripped the players and so vicariously served as the voice of the frustrated Nats fan. That's not what I look for in an analyst. That's the role of a columnist, blogger, commentators, etc. His job is to, uh, analyze the game on the field.