BYU is probably the most fiscally responsible college in America. We already had BYUTV up and operating for decades. Texas did not. They had to start from scratch. Their operational costs and cost to get started are much higher than anything BYU has to deal with. BYUTV already had millions of viewers around the world wit established partnerships with cable and satellite providers that have agreed to carry BYUTV. Texas doesn’t even have that. More people have access to BYUTV than The Longhorn network.

Byu’s Broadcast center was mostly funded by donations. They simply needed to put in additional infrastructure for HD and build an HD broadcast truck.

BYU has orchestrated BYUTV and it’s role in BYU athletics about as well as you possibly could. No, most schools including Texas can’t even pull it off. So that is the answer to your question on why other schools don’t do it.