I think the basic premise here is wrong. ESPN has figured out that there simply isn't enough content to fill a 24/7 schedule for sports. They also figured out that talk radio and cable news have a great business model based on 24/7 content -- sensationalist commentary on current political/social events -- that doesn't cost them a penny to generate. That's how you end up with "sports stories" in the media that used to be relegated to People magazine in print and "Entertainment Tonight" on television.
Why did it take 25-30 years for ESPN to figure this out? I’ll grant the network used to have more actual sporting events. They would tape delay Australian Rules Football and other events. However, we’re talking about a network with three live sports channels (ESPN, ESPN2, ESPNU), a dedicated news channel and a classic sports channel. In addition, they also run the SEC Network and Longhorn Network.
There’s enough sports and there’s demand for commentary. The problem is that the demand for commentary relates to the game on the field, not the off field politics. People want to watch breakdowns of previous games by sports commentators and they want to watch prediction commentary for upcoming games. People want to watch draft analysis without hearing about the sexual perversion of one of the players to be drafted.
Sports talk radio is boring as hell, it’s even worse when sports hosts try to talk politics.