Most of the carriers now sell unbundled ADSL now (AT&T, CenturyLink and I believe Verizon in non-fios markets.) it has more to do with distance limitations having too much of a downward effect on speeds. More than less subscribers are around the 5.5kf+ (kilotfoot) range, which usually means sub 15 megabit speeds - and a limited upload (inherent to all ADSL types).