Ofcom made their choice, they are a bit stupid if they think someone is going to build a new network to compete with openreach.
Given VM are spending £3 billion passing 4 million premises, and are about to start their 3rd group of FTTP builds perhaps not.
People won't build networks to compete with Openreach. They will build to compete with BT Retail, Sky, etc.
I know of a pretty large company that's awaiting the PIA changes and EU infrastructure directives with considerable interest.
EDIT: Hyperoptic have announced plans to use PIA too. With PIA to modern estates it's not actually that much harder to build to them than buildings. Pop some kit in the basement of a local MDU and branch out from there.
No-one is going to build everywhere but the areas that Openreach would have built FTTP to if they weren't dogmatically sweating the copper may see some action.
New, potentially affluent estates with high premium TV take up will be of interest.