Well, they're still competing with your local telco (AT&T / Verizon), DirecTV, Dish Network, and Google Fiber and/or others in some areas. (Though granted some of those are TV-only, not Internet.)
Not really much different than how Comcast and TWC are individually competing right now (as their service areas don't overlap). Though I'm not suggesting either one is a shining paragon of customer service or fair pricing (I don't have any first-hand experience to speak of there; I'm in Canada).