If you're gonna smash everything onto a single channel, you may as well turn the whole thing off.

Gonna look like absolute trash. Might be almost acceptable with atsc 3, except for the diaster of DRM and new proprietary audio codecs that brings.

Seventeen years ago, when we transitioned, the state of available and deployed equipment, codecs, and home receivers would not have permitted it.

I mean sure, you could pack four streams into one 6MHz channel. They could even be "HD" insofar as the transmitted stream is 720p or 1080i.

The result would have been MPEG-2 program streams of about 4.5Mbit each instead of about 18-19Mbit (assuming no other subchannels). That would make live sports or anything with significant motion look like absolute dogshit.

You might say that you don't care about that, and that is fine for you. However, in that case, I would respectfully submit that opinion to be far from the center of the bell curve of television-viewing American public of that era.

We could do a lot better with ATSC 3.0. So, there might someday be a second round of broadcast frequency reclamation, just as there was with ATSC 1.0.

Atsc 3.0 does this in a lot of areas, it is in my area, all the channels are multiplexed from one broadcast, although it's hard to tell on the tv since you get the virtual channel numbers that are different and the same as the atsc 1.0 channels