The move to 4k will be even easier considering many movies are already shot in it. Natural attrition will take care of it. It was much more difficult to change everything to a totally new technology where as this is simply a newer version of the same. They won't need to build new studios and such as they did for Hi Definition. Hi Definition was a much much more massive undertaking.
And as for 1080p. I believe several channels are already done completely in 1080p and downgraded for distribution. NFL network and I think espn are among them but not positive about espn.
Do any Directv receivers even support 1080p60? AFAIK, the 1080p they support is only 1080p24. That's fine for movies, but sports, not so much. No point in going from either 720p or 1080p to 1080p24 for that.
Don't assume that because HD is digital and 4K is digital that its just a software upgrade. Maybe they don't need a whole new studio, but if they replace all the equipment in that studio it is still pretty damn expensive. The cameras have to be 4K, there is 8x as much data passing around (assuming they go from 720p/1080i to 60fps 4K) They need new editing equipment, new encoding equipment, more satellite uplink capacity. I don't believe it will be as simple as you seem to believe.
Doing 4K for PPV will be easy, assuming customers will pay more for it to offset the cost of delivery. I could see HBO and SHO doing a 4K movie channel. But live action sports? Non-broadcast network content like Walking Dead or Salem? Color me skeptical. What's the point of providing a 4K feed if everything on it is simply upconverted HD?
SL5, PI-6S, SA-6AL, 3xSWM16; 21 H20-100, 1 H20-600, 7 H24-700/AM21