They will never move everyone over to Internet based Streaming ...
Theres a whole lot of people that have No interest in Streaming TV ... sure you young guys may be up on all that but the majority of people with D* are older ... I know I do stream a little, but thats only if theres something that I decide I want to watch that isn't currently on.
You shouldn't think of the forthcoming service -- which will essentially be full DirecTV delivered via the internet -- as "streaming". As others have said here, it will be accessed by an AT&T issued set-top box and remote control. It's going to feel like "traditional pay TV" to the end user, it's just that the signal will be delivered through the internet rather than via satellite or cable QAM. The remote control will have channel and volume up and down buttons and a 0-9 keypad, along with more advanced stuff like voice search/control.
In fact, I would bet it will be the SAME box that they use as the next-gen Genie Mini, the C71, which you can read about here based on AT&T's submission of the C71 to the FCC last fall:
DirecTV to Launch Android TV-Based OTT Set-Top Box (EXCLUSIVE)
The current Genie Mini is the C61, which is used in conjunction with the HS17 home server, which contains the actual satellite tuners and DVR hard drive. I'm betting that the forthcoming C71 can either be paired with the next-gen HS27 home server for satellite customers (which is hinted at in the C71 user manual at the FCC website) OR be used as a standalone box for those customers who get their service delivered via the internet rather than satellite. The user interface and overall experience will be very similar regardless of which way the signal is actually delivered to your home.
But, as AT&T has stated, the costs of new customer acquisition will be a lot less for internet-based customers than for satellite-based ones since the former does not require a truck-roll pro install, a rooftop dish, new internal wiring or the HS27 server. And they plan to pass a lot of those cost savings on to the internet-based customers, meaning they'll be charged regular monthly prices starting at about $80 instead of $120 for satellite. Yet they say they'll still be making the same margins on the internet-based customers. And given that the up-front acquisition costs are lower, those same margins actually mean a higher return on investment.
I don't think any current DTV satellite customer should worry that they will be forced to transition away from satellite delivery any time in the next few years. AT&T knows that the transition to internet-based delivery will be a long one and that there are a lot of folks, particularly in rural areas, who won't be able to switch since they don't have quality home broadband service available (yet). Data caps will also be an issue for some multi-person households; Comcast internet is plenty fast enough to support all the video streaming you want but if you exceed 1 TB in usage in a month, you'll incur extra fees. AT&T has a similar data cap policy for their home internet services, although I'm sure they'll waive that for DirecTV streaming if the law continues to allow it. (Strict net neutrality laws pending in some states, like CA and OR, may preclude them from zero-rating data for their own TV services.)
What will be really interesting to watch next month is the ruling handed down on the AT&T/Time Warner merger. If AT&T is required to spin something off, as the DOJ wishes, as a condition for the merger to go through, AT&T absolutely will NOT spin off the Turner channels. Owning that content, with the ability to earn lucrative targeted advertising fees on those channels, is a key part of their future strategy. The other option on the table for divestment is the DTV satellite service. I think AT&T would be loathe to unload that right now too, since they want to be able to transition those subs over to their forthcoming internet-delivered service. I do foresee them spinning off satellite TV a few years down the road, once a majority of those customers have transitioned over to internet-delivered TV service. But if the choice was between completely calling off the merger and divesting the satellite TV business right now, which would they choose?