As others have stated, these new $50 and $70 DTV Now packages are just not a very good deal relative to YouTube TV, PS Vue, Hulu Live or Sling TV. If they would have made HBO an optional $15 add-on and priced the packages at $35 and $55, they might get a few more subscribers. But I kinda think AT&T doesn't care that much any more how well DTV Now fares.
These streaming "cable TV" services seem to get a whole lot of attention among cord-cutters but most of us instead simply subscribe to one or more on-demand services -- I currently have Netflix, Hulu ad-free, and Prime Video -- and supplement that with free options like YouTube, OTA TV, etc. I don't personally miss cable channels, but then I don't watch a lot of sports, which to me seems to be the main reason to still subscribe to cable TV.
On the one hand, I think it's a good thing that these services like DTV Now and PS Vue exist, as they provide consumers with additional options. But I tend to think that most people who would keep a cable TV package year-round are probably just better off, overall, bundling TV service in with their broadband from the same provider, especially if they're willing to commit to a contract. If your TV needs are modest, or you're flexible about which channels you get, how your DVR works, having to jump into different apps for different channels, etc., then you can probably save a little money by going the streaming route. But it seems like the industry has made these streaming alternatives just inconvenient enough that the majority of folks wouldn't switch over to them.