Virgin Media vs wholesale
"The challenge on Virgin Media as a viable, alternative infrastructure provider is that they have no wholesale haul and a system stack that makes its extremely difficult for unbundlers to connect with"
Well, Dido, what makes you think that VM have any interest in sharing their own infrastructure with other companies? If they had, you'd have an offer on the table already.
If I was VM I wouldn't do wholesale either, unless I was desperate to make coins. It's their unique selling point to have their own broadband/fibre infrastructure. You don't give that away just because less capable companies haven't managed to build anything similar; and given the regulatory pressure you expose yourself to when you allow others to piggyback on your infrastructure, you try to steer clear if you can.
Of course that's hard to grasp for companies that wouldn't be able to offer any broadband at all if BT wholesale didn't enable them to. For BT it makes sense, because it was a former state monopoly. Virgin don't have that sort of heritage and don't per se owe the country or other ISP anything.