Power pair laid in with each fibre?
well - there’s already copper pair to each home so no need to lay it. But the costs of maintaining that copper infrastructure just for power delivery (or even for “everything that isn’t fibre broadband”) exceed the benefit given that most of us only want fibre broadband from our fixed-line suppliers.
My smartphone battery lasts all day - so as long as one of the nearby cell-sites stays up I can contact emergency services just fine. Heck, if I walk out into my garden I can do so by satellite.
When I was a kid the post came twice a day. But no longer. The world moves on.
Incidentally you could probably even deliver a few watts of power over fibre if you really wanted to (modulo finding a point downstream of any PON split where power and battery were available - I’m not sure whether OpenReach co-locate their PON splitters with their legacy cabinets, or whether they connectorise things there or just splice - and of course issues of cost, power efficiency, safety etc.)