Cable TV seems to be moving to Streaming TV from the Internet. Do Army Barracks have Cable TV ethernet modems like they do for civilian side?

Depends on what the Unit is authorized to have in the Day room or the WiFi capabilities of the Unit if allowed ...

So I use ROKU boxes to my TV's and live streaming (where it exists) to my TV sets. A lot cheaper and more customizeable than Cable TV. AT&T seems to be moving in the same direction as well with a streaming TV Offering comming out next year which will go for about $45 all inclusive. So I am curious if the newer Army Barracks can accomodate this already?