An uncompressed SHV signal has a bit-rate of 24G bps (bits per second) and that's unmanageable for broadcasting systems. It needs to be compressed. But real-time encoding and decoding of such a high-bandwidth signal is also a challenge.
Uhhhh, YOU THINK?!?! 24Gbps?!?!?! Hahahahahahahaha!
I haven't even bought an HDTV yet, let alone be concerned about the next gen broadcast standard. Heck, the FCC is still flip-flopping with broadcasters about switching from analog to HDTV. Plan on HDTV being the standard in the U.S. for a long, long time.