"In the first three quarters of 2017, cable companies added about 2,000,000 broadband subscribers, while Telcos lost about 430,000 subscribers." Bruce Leichtman. Ten years of telco dis-investment across half the United States is allowing cablecos to rise from 55% of the market to 64%. They are pulling further away every quarter.
AT&T's stock went down $13B on they day they warned about disappointing numbers. If they had spent even a fraction of $13B on investment, their numbers would have been fine. Verizon's investment % has gone down for several years; this quarter, they lost 10,000 broadband customers.
Frontier lost 63,000 subscribers, The stock has gone down 85% this year to a level that implies a serious bankruptcy risk. That is unlikely before 2020 because they don't have large debts coming due. They have been dis-investing for years, with capex less than depreciation. Centurylink lost 101,000 for the same reason.