The boxes are very different than they were years ago. The typically have a HD of 1TB or more built in. They also are used to provide the channels being paid for without the box there isn’t a good mechanism to have the proper channels for each consumer.
Xfinity will also be providing apps lke net flix.
The cost per MB of data services are far lower than in the past.
There is a very good alternative to provide the proper channels for each customer without a box, a cable card.