Yochai Benkler in the New York Times explaining ultimately why network provision and retail access to it need to be structurally separated:
innovation happens in electronics and services — not in laying cable. If every company has to dig its own holes, the price of entry is too high and competition falters; over time, innovation lags, and the goal of broader and better access suffers.
Existing local companies argue that they deserve control over a market because they’ve sunk enormous amounts of money into digging trenches and laying cables for their telecommunications network. And to be fair, it is expensive. But other countries are exploring creative ways for competitors to share the costs and risks of fiber investments, sometimes coupled with public investment, so that incumbent companies can accommodate competitors without unnecessarily hamstringing themselves.
Making such an arrangement work is ultimately a matter of political will.
Read the whole thing (not behind a paywall at the moment) – he's talking about the US but we have a very similar (possibly worse) situation here … and that last sentence is where the issue lies