We have recently had fibre-to-the-premises installed (by BT). It involved Openreach running a new cable from the telephone pole in the road to a fibre modem/box which they fixed to the wall inside the house. It needs power, so it had to be fitted near a mains wall socket.
The copper wire telephone connection inside our house (from the master socket to the phones) was not changed.
The new BT wireless Homehub plugs directly into the new fibre box on the wall.
Our broadband speed has increased significantly to an average of about 60Mbps (download) and 20Mbps (upload). Previously they were about 7Mbps and 2Mbps respectively.
It took the BT engineers about 2 hours to complete the installation. We just pay the monthly charge - we didn't have to pay any one-off or extra charges for the new cabling and fibre box to be fitted or for the new Homehub and "disc". The disc is effectively a wireless booster/repeater and is placed away from the Homehub to improve wireless signal strength in any part of your home which normally has a weak or no wireless signal. BT will send multiple discs free if necessary, so your house is fully covered.
BT is trying to roll out fibre to as many properties as possible, so you're right in that they are replacing old technology at every opportunity.
Last edited by Blues&twos; 18th Oct 2019 at 18:33.