This is exactly what the Baby Bells are required to do with their lines. This is why you sometimes see small regional DSL providers - they're leasing the lines

This is exactly what the Baby Bells are required to do with their lines. This is why you sometimes see small regional DSL providers - they're leasing the lines from the Baby Bell and reselling them. That might also be why the two companies doing really shady net neutrality stuff are both cable providers rather than DSL providers - the DSL providers wouldn't be able to get away with it.