I personally would love it. I hate arranging conference calls only to have one person miss, no matter how I phrase the invites. "That's 9 am Mountain time, which is 11 am for you, Steve." Means Steve will call me at 7:10 Mountain time and say, "Where is everyone?"
But why not: Inertia. TV producers will bandy about some straw man like, "Shows are used to delaying by an hour for Central, two for Mountain, and the odd hour out for the West. The common announcement that "x will be shown at y:00, z:00 West Coast" will have to be changed to "x will be shown at y:00, y-1:00 Central, y-2:00 Western, and some other time West Coast." The additional seconds it takes to say that will result in less advertising which will destroy our economy." That cable, satellite, DVR, and streaming have already made that argument pointless will not be understood by said producers or the politicians who listen to them.
Besides, enough voters don't understand. Remember, we're smart and in the minority.