We've already lost the landline and everything has to be done over VOIP to save them money whilst making sure that in a power cut we lose the phone line entirely and have to rely on the very poor mobile signal around here.
That's not entirely correct and somewhat disingenuous. The problem with the old (soon to be discontinued) voice service is that it's getting harder and harder to find anyone willing to make the kit or spare parts for it. Anyone who does is charging an arm and a leg for the privilege. Hardly anyone uses a landline these days, those that do are probably using DECT units that are reliant on power and in any case power cuts of any significance are so few and far between that it doesn't really matter.
That sucks if you're a 90 year old living in a remote cottage relying on two miles of pole supported, tree threatened, copper for your phone using a Bakelite handset but for everyone else it's all very 'meh'.
For decades now BT has been maintaining a VoIP service hidden from customer sight behind AD/DA converters in the exchange. It is a technically archaic solution and the time has come to do away with the duplication and decrepit equipment just shift everything onto IP.