As with HBO, ESPN makes a fortune from the subscription fees paid by cable providers. There are far more people who have cable/satellite than have the ability

As with HBO, ESPN makes a fortune from the subscription fees paid by cable providers. There are far more people who have cable/satellite than have the ability to stream to their televisions. As such, they get more eyeballs -- allowing them to charge more for advertising. This war chest begets more broadcast rights deals with the major sports league which further cements their market leading position. Their analysis indicates that they would be unable to replace revenue in a purely streaming subscription model so they will be with cable until it can.