I still would have preferred a solution, something on the lines of having a thin copper wire(s), running along the fibre cable (bundled together), between the street cabinet and peoples homes. Then it could be designed to carry on working, even if there is a power cut.
I think it is not the copper wires that are the expense, it is the telephone exchange at the other end of the copper. Think a large building with battery banks and chargers and racks of equipment and so on that have to be maintained.
This is true to a certain extent. Open Reach, the UK network provider, inherited all the infrastructure when they took over BT. That infrastructure was developed over many decades by the predecessors to BT, GPO telephones and Post Office Telephones. It comprises of a huge number of exchange buildings, admin offices, engineering centres etc, etc. So for any given area, there will be at least one exchange building, in rural area's this will be very small and unmanned, literally a brick shed with an emergency genny, back up batteries and the exchange equipment. As the area's increase in population density then the buildings become larger with more equipment, but rarely manned.
This issue is complicated by virtue of retail service providers, like Virgin, EE, etc, etc, who will have their own exchange equipment on the racks for their customers, configured for the packages they provide, but all maintained and serviced by Open Reach who charge the retail providers accordingly. So it's a complicated story, as always though, because of the commercial agenda, it's the consumer who will suffer the consequences of network development. Open Reach is guilty of rolling out high speed BB at a snails pace, particularly in less populated area's where the return is much slower, and this despite pressure from succeeding governments to get the job done. Problem is with Open Reach is that they run with the hare and the hounds, providing both Infrastructure and also retail services, so they have a vested interest to prioritise their own customers and hold back competing providers.
For example, I've been on the Open Reach service update list for fibre for over 10 years!!! And until this fault revealed that it was available in my area I was unaware of that!
This is a big problem for the UK, their policy has held us back with poor BB service and speed, whereas in other parts of the world they've had gigaspeed BB for years!!!
So now, by the time they provide coverage for all the UK, technology will have made it all obsolete!! As has been mentioned, it will be 5G mobile in a short time.
If UK government had invested as heavily in communications as they have in useless and pointless green energy policy, the whole country could have had comms technology that would have actually been beneficial.