Time Warner Cable is not part of Time Warner, so they're not consolidating service providers. AT&T just wants some content production companies.
https://en.wikipedia.org/wiki/List_of_assets_owned_by_Time_W...
It seems like sports is the last frontier that's keeping traditional linear TV alive. Nobody wants to stream the game tomorrow; the outcome is already known which makes it unexciting to watch. Time Warner has plenty of exclusive sports deals, which gives AT&T leverage over their competition that also has exclusive sports deals (Comcast is the big one). If anything, this creates some incentive for cross-licensing that didn't exist before, which could in theory be good for end users. (I'll believe it when I see it, though.)
Alternatively, traditional TV still has a lot of money behind it, so it makes sense to keep it alive for as long as possible. If you couldn't buy HBO Now and you like HBO shows, your "only" choice is to buy all the channels you don't watch in order to be able to watch HBO. That would be good for both the cable company, and those other channels nobody wants. If a cable company controls HBO again, I think we can see where this is all headed.
Personally, I don't think AT&T can really afford this acquisition, so it might be the beginning of the end for them. If I were AT&T I would spin off everything that wasn't my spectrum licenses, and have a handful of employees raking in pure profit without having to deal with the pesky business of building infrastructure, producing television, billing customers, etc. Kind of like all the companies that own airplanes and lease them to the airlines, or I suppose DeBeers and diamond mines.