Each telco has their areas where they own the facilities, building, wiring, employees....
For another company to enter that market would be an over builder who starts from scratch. Good example is Google Fiber in the few cities they entered, years to build out with low ROI which is why Google stopped and looking at providing wireless internet.
ATT is in the midst of a 4 year (2016-end 2019) deployment of direct fiber offering speeds of 100, 300, 500 or 1000. By 2020 about 18% of their 21 state footprint will have this service. With over 80+% not having direct fiber I would not expect them to enter a new market to provide service(s).
As the next decade will have 5G wireless, mmwavelength and possible Project Airgig, if ATT expands into new markets it would most likely be offering wireless service. In many cases if within range of ATT cell tower you can already receive WHPI aka hotspot from an ATT storefront.
Edit... Frontier has grown by buying unwanted areas. A few years ago they bought the old GTE, Verizon markets in California, Florida, and Texas. In the 1990s they and CenturyLink bought rural areas from Ameritech 5 states. In Wisconsin lower rural parts of state are now CenturyLink although some areas that were rural in the 90s are not today. Upper Wisconsin is Frontier, I expect the same happened in Ohio.
ATT (SBC) even sold their Connecticut operations, SNET to Frontier around 2013-2014 with 3000+ employees being now Frontier employees.
The only time/area I know of ATT overbuilding into Frontier territory was a few years ago in the Raleigh/Durham tri county as part of government bid process won by ATT, I think they even beat Google but could be wrong if Google did not submit a bid.
Bottom line, if your ILEC is Frontier do not expect ATT unless willing to move to an ATT area.
Just my thoughts....
*I am an AT&T employee, and the postings on this site are my own and don't necessarily represent AT&T's position, strategies or opinions.