One of the things that really helped is that all passive telecommunications infrastructure is by law "common use" - so things like ducts, pipe work, man holes, poles, etc can be used by any company. This has really helped to level the playing field so a single company doesn't have an unfair monopoly because it was there first (cough BT cough). Where I'm living right now cable and DSL was available (maybe up to 50mbit?), but last year fibre was rolled out by a different company. There are also guidelines on how the infrastructure should be delivered within buildings, so most apartment buildings have duct work going from the basement to the top floor, and space for the providers equipment for future upgrades.
Where I live in the states, telephone pole access is "common use" but the bureaucracy around actually being able to do so makes it pretty much impossible to add new lines (eg: needing to get a expensive environmental review for adding a wire to a pole that already has wires). Last I checked it took about a dozen permits which took ~12-24 months to get. After you got the permits, you then needed to pay for the inspection and full replacement of any poles found to be old/substandard that you wanted to attach to.
Edit: Looks like Ofcom wants to do something similar: http://www.ispreview.co.uk/index.php/2016/02/a-closer-look-a...