What is needed is for some 'cheap compatible hardware' to become available to provide the Vectoring Infrastructure which may encourage BT to spend some money.
The vectoring tests that BT did previously were with a generic FPGA DSP - which *might* mean it would run on the DSP's already installed in the Huawei DSLAMs. It could be just a software change to enable vectoring.
The current field test is with ASIC hardware (ie specifically-designed hardware). I imagine they are testing to see if there is a difference in performance, to decide whether it is worth using fresh hardware.
I recall seeing, a while back, an estimate of the lifetime costs of FTTC; that suggested that the lifetime of the DSLAM electronics within the cabinet is about 8 years. That might mean that BT would be expecting to have a programme to refresh the hardware - which might then be the point that vectoring-specific hardware gets added.
Either way, I imagine that the contract that BT has with Huawei pays for the feature-set used; if BT turn on vectoring within existing hardware, I'd imagine that Huawei would be due some extra dosh.
(Although I really expect another 'BDUK type event' will happen and we (Joe Public) will end up paying for BT to upgrade their network again )
I imagine that this could well happen.
However...
What BDUK has paid for, in these rounds, seems to include dark fibre delivered to (the vicinity of) nearly every cabinet. The majority of properties served nationwide are within 1km of their cabinet - and this is true whether the cabinet was upgraded commercially or with BDUK. The real difference in viability was the number of properties served by the cabinet, plus the ease of getting fibre/power to the box.
The next round of upgrades are likely to be either FTTP/FTT-outside-wall or a hybrid with FTTdp. The decision about viability there is likely to be based around groups of 10-20 houses.
It strikes me that the FTTC-based outcome, with dark fibre, of this set of BDUK projects is likely to make "rural" groups-of-properties just as commercially-viable for future upgrades as "urban" groups-of-properties. The distance from "cabinet+dark fibre" to "group-of-properties" is likely to be similar (at least for a good chunk of "rural"), and it might even be easier/cheaper to feed the fibre in rural areas.
If you think the situation in the UK is bad, see Australia and their 'NBN'
Australia is a strange case - they do actually seem to have problems with the quality of the copper. I read that, for a while ten or twenty years ago, they'd been sealing copper joints with some gel of one sort or another. It turns out that this was a bad move - causing corrosion up to 3m either side of the joint. That makes it questionable as to whether their copper really is up to the job of carrying FTTC!
http://www.abc.net.au/technology/articles/2013/09/19/3851924.htmOther than that, they've done one of the hard jobs of a fibre rollout - getting together a single, nationwide plan, getting the infrastructure owners into that plan, and figuring out the funding. Politics & economics are the problems, not the technology...
OK. They've utterly changed the technology they're planning to use in the newer "mixed" model - but I tend to believe that we have the technology to meet whatever plan we want to go for. The hard part is getting an agreement on the plan, and funding it.