@tickmike - Yes, I understand the term passive; I wondered why it is felt to be an advantage having passive kitz when there is power available - at the end-users’ premises.
In contrast in some situations there is no practical local source of power at all, not close by; one example is the undersea BT network in the Hebrides in the Clyde Estuary and from Caithness to Orkney, which was put in place about, what, five years ago, where the network could be achieved repeaterless and so no need for dangerous and expensive power cables to seabed repeaters; dangerous because of the risk of fishing vessels hooking up power cables by mistake.
Coming back to FTTP with power; there would be of course the hassle of having to run copper power condition cabling alongside the fibre, although the cable can be rubbish quality, but at low voltage the losses could be substantial, so some design choices there, and there’s also the problem of some end-users turning off their power supply, either stupidly or for other reasons, but anyway, intermediate nodes would need to be able to run on some reduced subset of the available power lines