/lecture mode:
Cable channels, unlike oldschool broadcast channels, get their money from two sources: the first is advertising spots (like broadcast), and the second is what the cable systems (Time Warner, Charter, Comcast) pay the cable channels to air them every month (usually called carriage fees). E.g. if you're a Time Warner customer (like me), roughly $6 of your bill every month goes right to ESPN*. (By contrast, AMC, back in the Frank Darabont-Walking Dead mess, was getting a mere $0.26 every month per customer.) This is why if you want certain channels, you have to subscribe to extra packages (because your cable system doesn't want to pay that price for every subscriber they have), or why it can take so long to get a cable channel added to your system - it took forever for the NFL Network to get added to Time Warner, because the NFL wanted it added as a basic package channel (so Time Warner would have to pay them for every subscriber), while Time Warner (obviously) didn't want that.
The rise of digital and a la carte systems could put a serious dent in the the likes of ESPN, TNT, etc.'s bottom line... in about a decade or so. The more likely case is this is just another once-a-decade spring cleaning, where expensive hosts get released and the network carries on. How many 20-somethings even remember when, say, Craig Kilborn or Dan Patrick were on the network?
*All those college bowl games you've never heard of until recently? They're completely "fake" entities created by (and owned by) ESPN, because they earn more in advertising spots than it costs them to hold the events, and raises the carriage fees they can charge the cable systems per month.