Vectoring isn't going to help massively with that, what would help I suppose is G.Fast but if you're going to run fibre to the DP why not just run it all the way to the home...
I guess the answer comes down to cost, and lead time.
Averaged everywhere, the cost of fibre between all homes and the DP makes up the biggest portion of the engineering cost ... including all the nasty parts such as MDUs and direct-buried lead-in.
It isn't a long distance, averaging 35m, but there are 28m leads needed. Conversely, there are only 4m DPs, averaging 350-400m from the existing cab.
But BT appear to be driving longer-range G.Fast, so I suspect they'd aim at 500k nodes, not 4m, averaging 250-300m from the existing cabs.
Still, I imagine the numbers allow for FTTP in easier, cheaper places.
As for lead time... if Openreach swapped to FTTP in 2018, you'd probably find a 15-year+ rollout is the result. Those places at the tail of the queue, likely today's notspots, will find they have to live with today's super fast solution.
One touted benefit of a hybrid solution is a faster rollout ... and BT think g.fast will still be a 10-year rollout. Will rural areas cope with 24Mbps for the next 10 years?
Vectoring helps too. Not everywhere, but some places, certainly. Perhaps 85-90% of premises. It helps speeds, sure, but better, it improves speed consistency and range.