One of the (many) reasons governments should not start or run businesses it that they have an irrestible urge to rig the game in their favour. Competition is wasteful and competitors usually try to just take the best bits of a market.
The NBN Implementation Study suggested that there could be a levy to discourage its competitors (Telstra) from cherry picking by supplying an optical fibre service to businesses in CBDs. “If we must supply fibre to 90% of the population, including many people who don’t need it, Telstra should not be allowed to provide it to those who do need it”. (My paraphrase).
Optus agrees. If there is to be cheap rent about, you can bet that companies will seek it.
I do hope that Telstra will not sell its pipes and ducts to NBN and remain as a competitor, but I suspect that NBN cannot afford to have competition so the government will make Telstra an offer it can’t refuse.