I believe at first, SpaceX was squeezed out. SpaceX sued the government as choosing a monopoly. The government then went back on that to allow SpaceX to play.

There has been a lot of commentary in the news as to why SpaceX may not have been chosen. They don't have the track record that the current "monopoly" has. Even though SpaceX can deliver cheaper, these loads aren't nearly as price sensitive as commercial loads. SpaceX hasn't yet shown they can deal with increased load of launches.