There's two angles here: * cable networks can get more revenue for a lot of types of sports than broadcast. ABC and their affiliates can make more in ad revenu

There's two angles here: * cable networks can get more revenue for a lot of types of sports than broadcast. ABC and their affiliates can make more in ad revenue from their regular programming than by showing random college basketball games every night. * there's only so many broadcast channels anyway. ESPNU can make money from every national cable subscriber without having to find and pay a broadcast station in every single market. The reason ABC can't afford to be sports-only is about both the cost of the sports content and the opportunity cost of using that spectrum just for sports. And yes, Disney owns ABC and ESPN both. But that's because ABC chose to buy ESPN in the 90s than risk getting shut out of the sports game entirely. ESPN was a disruptoer before it was part of the establishment. And a lot of today's ESPN content didn't come from ABC/NBC/CBS in the first place - early-2000s college sports, for instance, were broadcast by a lot of regional affiliation networks that were often shown OTA on various non-major-network stations in the conference region. Things like the B10 Network and SEC Network (aka ESPN) killed those because cable money (or the gamble that the cable money would be there, for the Big 10) let them outbid the old groups.