I can't believe this is 2017 and I have to ask about HD channel availablity, but...
I'm in the Chicago area, and none of these channels are available in HD:
ESPN Classics *
* I think ESPN Classics and Antenna might not broadcast in HD, but the others do.
Also, most of the premium channels besides the main one (ie. HBO Signature/Family/Comedy, MMAX, AMAX, SHO 2, SHO C, SHO X, etc.) are not HD.
What's the reasoning behind not offering the HD version of these channels?
ESPN Classic, Antenna TV, Me TV and Me Too are not broadcast in HD anywhere, regardless of the provider.
GSN HD is carried in many Comcast markets already and has been for years. As for why it's not in the Chicago area, that one is beyond me.
No Comcast market carries TV Land HD.
The reason not every channel is in HD is due to bandwidth and programming contracts. Comcast has prioritized using its bandwidth for internet capacity over additional HD offerings, which is not the path that other cable companies have done. Comcast had more of the HD premiums in the Chicago market and other markets, and removed them to put other channels (like GSN in many markets) over those additional HBO/Cinemax/Showtime feeds.
beIN Sports is another channel not in HD with an English audio track in the Chicago market. The channel is available in HD but with the Spanish audio track. Why can't they put the English track as the 2nd audio track on the Spanish HD feed?
Also, channel 1002 for CBS2 is in SD and not HD which is annoying now that NBC5 and WGN9 are not at 1005 and 1009 respectively.
As for the HBO feeds, I keep them in my guide but if I see a movie that I want to watch I stream it in HD instead of watching on the SD channel.
You are talking about shows that were never produced in HD form. They were prduced long before HD televisions came to market.