The answer is simple: total lack of investment (it was pretty much treated just like DirectTV).
I (used to) watch (or try to, at least) Crunchyroll. I've watched it deteriorate since AT&T got it. Dropping support for a lot of devices, like the smart TV apps. The remaining apps getting glitchier and glitchier. It became impossible to use the add-supported app, because it would just freeze up when showing a commercial break, and you couldn't continue.
My son-in-law has connections inside Crunchyroll (he works in the business of bringing video games and Anime to the USA), and he says that it was just unwillingness to spend anything on the business and willingness to drive away all the best people.
I let my paid subscription lapse almost a year ago because of the issues. AT&T is getting rid of it because they are shedding subscribers and AT&T doesn't want to invest to fix that.