1080p/60 isn't going to be a broadcast signal with the current bandwidth & MPEG-2 encoding.
Not to mention it isn't part of the HDTV standard that the Grand Alliance came up with in 1993 and refined in 1997 or 1998 (I can't remember which). It has been updated since then but the basic parameters of HDTV haven't changed. 1080p remains outside the standard.
Beyond the practical ones mentioned by VOS
, there are huge marketing considerations. We here are cutting edge folks. The general public isn't. Imagine the hue and cry from your next door neighbor who finally bought his first HDTV last year, spending $299 for a 32" Samsung that's only capable of 720p, when he finds out that his set can't receive ESPN because they just switched to broadcasting 1080p. There might be enough of an general outcry that even Congress would get involved. These are FCC standards, after all.
As much as we might like greater definition in broadcast technology, 1080p isn't going to be a broadcast standard for at least a dozen years. People don't like change this rapidly. Widespread acceptance of Blu-ray has been slow. Lots of people still have a row of VHS tapes on a bookshelf at home and their DVDs look perfectly fine, thank you.
The lack of consumer acceptance of 3D television isn't just because of the funky glasses you have to wear. It's because 95% of the folks out there are happy with the new HDTV they bought just a few years ago.
You can't force feed new technology on the public. They will reject it and it will fail.
Edited by Carl Spock, 10 August 2012 - 11:48 PM.