I wonder if it anything to do with
this.
current market regulation could still prove to be a difficult hurdle because Vodafone may well demand some degree of exclusivity over any jointly built infrastructure (e.g. initial sole use of the infrastructure and first access to the fastest speeds etc.), which would obviously upset rival ISPs in a market where Openreach is required to provide fair and equal access.
If it is, then in a way I can see their point. They invest a shedload of £... but have to open it up to anyone that wants to piggy back and cherry pick the more profitable areas.
Vodafone was one of the few who could have invested (and I had hopes would) in an alt network.
Yet absolutely zero other network providers are made to open up their network in the way that Openreach is. VM has the sole cable network but are not subject to the restrictions that Openreach are. In this particular case I should imagine it would have given Vodafone something to think about when it comes to any joint venture with Openreach that just would not apply if investing with any other telco.
Whilst I fully support that there must be a regulator, I sometimes think that role out of full fibre in the UK would be more advanced if it wasn't for some of OFCOMs restrictions :/