I think thier idea of moving everyone from D* to D* Now (if that truely was thier idea) had NO Chance of working.
They were never going to get all DTV subs to switch to AT&T TV (and I don't think they believed they could) but they could still get a good chunk of them to move over if they take the right steps. I've already seen posts from longtime DTV subs who've made the switch to AT&T TV and are happy with it. Obviously, they were never going to get folks without home broadband to switch over (which is why AT&T admitted a while back that the target market for DTV going forward would shift to mainly rural homes without broadband). And as long as NFL Sunday Ticket remains exclusive to DTV, that will keep some folks there. And some folks just hate change, so they'll stick with what they have until it simply stops working.
But if they made just a few improvements to AT&T TV -- and nothing that's even technically challenging, just stuff like extending the cloud DVR retention from 90 days to 1 year, adding PBS locals, adding the same 4K HDR content DTV has, etc. -- then there really wouldn't be any significant ways in which DTV was better. Meanwhile, AT&T TV already has various ways that it's superior to DTV (unlimited DVR storage, no tuner conflicts, better equipment with streaming apps and Google Assistant on board, option to save money by using your own streaming devices instead, ability to access the full service on any screen in or out of home). As far as HD picture quality, the consensus seems to be that it's a tie.
But just making AT&T TV a little better than DTV wouldn't be enough to get all that many longtime DTV subs to switch. It would need to cost less too. And the regular pricing for AT&T TV is a little less than it is for DTV. And the more TVs you have and the bigger your channel package is, the greater the cost savings. But lots of DTV subs get loyalty discounts that take significant amounts -- $50 or more -- off their bill for an extended period. The only way those folks would likely switch would be if AT&T offered to transfer those discounts to AT&T TV or if they just did away with all those discounts and charged everyone the regular price.
Then when someone called in to complain about their DTV bill, they'd just offer to switch them to the same package on AT&T TV for a little less. "You'll get a better service and pay less each month" would be the sales pitch. They might even incentivize longtime DTV customers to switch over by offering them free AT&T TV boxes, which normally sale for $120 each, or $5/mo spread out over your first 24 months.
All that said, who knows at this point what they're thinking is in terms of hoping to shift any DTV subs over to AT&T TV. If they have things priced so that an existing sub on DTV (post-contract, after the cost of installation has been recouped) is just as profitable as a new one on AT&T TV, then maybe they don't care if they stick with DTV.