All of these people entering any sports talk programming, radio, TV or internet, learn one word quickly from the program directors and directors and it's the same word program directors use with morning show talent, compelling. It is the single most important element for their success.
Once upon a time, they used Q Factor Research to gauge the level of "likability" before putting someone on the air but now that has changed. Doesn't matter whether you like someone like Bayless, Sharpe, Smith or Cowherd, only that you watch them. Look at how many clips are posted by posters here of people they do not like. They are not only compelled to watch but compelled to share them with others. "Here, hate this guy with me".
However, it is important to stay in the role one is known for and not break out. It is going to be most interesting this season with Bradshaw calling Rodgers "dumb as a box or rocks", don't think we've heard the last of this. Bradshaw should have said "Rodgers couldn't spell cat if you spotted him the c and the t" that Hollywood used about him, much funnier.