This is one of the areas that CCK or the regulator that replaces it should look at, I have heard Soliton Telemec complaining of the same here in Nairobi. Operators still view fibre as a strategic installation and use it to lock their competitors - Haile Selassie Avenue has cable from more than 6 operators running along it.
The challenge, will however be the familiar one of implementation, in case a law is passed making commercial and rental properties vendor neutral. The best bet is for operators to partner with vendor neutral property owners to showcase their property as having more advantage by allowing tenants to pick from a variety of ISPs.