That is why you should always avoid your ISP modem/router combos.
A) $50/month with your own equipment and a data cap
B) $80/month for the same as (A), but unlimited data
C) $60/month for the same as (B), but higher bandwidth and using the ISP's equipment
What horrible things are they doing with that router that they would effectively pay you $20/month to use it for
- they get some data on how many (and what) LAN devices you have
- they face fewer support calls from people using DOCSIS modems with one of the buggy intel chipsets, and from people with a random router/modem combination that their support people aren't trained to debug
- they can expand their wifi hotspot network (the xfinity wifi hotspot is enabled by default, but the user can turn it off)