navychop said:"...Is that not the plan for ALL channels to go to HD at some point? ..."
No. All channels will go digital, but not all HD. For decades, there will be reruns of SD programming- some stations may specialize in this. Some source material will be of limited interest, and not support the added expense of recording in HD. Bandwidth will always be a concern, so HD programming must be of great popularity to pay the freight.
Sadly, multi-casting will always be with us.
Yes, but at some point everything will be in HD... its just like everything else out there. There will come a time that it will cost more to broadcast in SD, or to even record in SD, so things will transition to HD all over. I could see even the "SD" only channels being broadcast on an "HD" channel, but still only showing up in SD resolution.
Bandwidth is always going to be an issue of course, but there will always be newer ways of increasing bandwidth, so its just a matter of when E* decides to implement those new methods. Its not a matter of IF, but a matter of WHEN.