Most likely cost. It became too expensive per premises to be considered value for money. May come back into scope via FTTC or FTTP.
Agreed, on my exchange which was mostly to be FTTP and rest as FTTC as part as the Commercial rollout back in 2011.
Most if not all the FTTC and a small percentage of the FTTP were completed back then leaving the rest partially completed.
BT are now coming back to complete that work still as part as a commercial project which is now due in 9 months time (i.e. Feb-Mar 2018) so the old commercial rollouts are starting to be done.
Granted depending on what has already been put in place before the halt will result in what gets rolled out in that area, some are still FTTP whereas some areas are being pushed back to FTTC.
I know a lot of Commercial work in London got put on hold in favour of BDUK contractual dead lines.