People may hate the standard, but 1080ix1280 and 1440 are in the official standards in several places. Most obviously in satellite to home standards.
http://www.atsc.org/standards/a_81.pdf e.g see table 7.3
More important can be bit rate. Bit rate starved 1080x1920 can look awful.
And of course I don't think they added mpeg4, used in these new channels, to the atsc standards, yet.