If you google this, you'll see that eventually that was the whole reason why AT&T bought D*; it's too costly to maintain the TV platform, for only around 6 million subs, compared to D*'s 20 million.
Also, if you go to their own website & try to qualify for U-verse TV, they NO longer even offer it as a visible option; they ALWAYS push you to D* TV service instead now. If they were, indeed, planning on keeping U-verse TV alive, they would NOT be doing this...& SO quickly before the ink could dry on their D* purchase completing.
Then they're SOL; it's not like AT&T hasn't ditched customers before for "technology changes"; there are LOTS of AT&T DSL subs, that are now SOL when they could NOT be migrated to U-verse internet, due to (shorter) distance limitations; AT&T is NOT concerned about the loss of a few subs like this, obviously.
And why couldn't this happen???