BT executives took the crazy decision to attempt to turn a communications company into a broadcast media company. It wasn't what the customers, the British Public, wanted as a service or needs long term. As a consequence investment in new infrastructure was focused on a latency insensitive asymmetric broadcast network. It's not useful for voice communications nor the Internet of Things, just music and video downloads. The money spent on FTTC gives a short term advantage, but is a technology cul de sac. It is in effect, wasted money when BT should providing a fast symmetric low latency network. Along the way it should be bringing its neglected ducting into a good operation state.
Sadly it needs Government (OFCOM) intervention to force BT to do the right thing. Apportioning the cost of maintaining the edifice should be shared amongst the tenants, but that is just a matter of billing.