My own view is that there is a clear need to retain landline phone connectivity, that works for a useful length of time if there's a power cut, for those that have no other means of making an emergency call. Right now, our VDSL/FTTC service categorically does not meet that requirement. Certainly VOIP works well using it, but as it dies not long after the power goes off it's about as much use as a chocolate teapot as an emergency phone service.
However, my understanding is that when we get FTTP then this situation goes away, as FTTP does not need power in cabinets to work. Providing home backup power to run the ONT etc is easy and something that shouldn't be difficult for those in areas that lose power. Same goes for powering the router and ATA or whatever.
Therefore it seems to make sense to delay the PSTN switch off until such time that FTTP is available, as that neatly sidesteps the major reliability concern with no need for any additional work by service providers. The fibre programme is already rolling out at pace, so as each area becomes fully FTTP enabled then that should be the time to turn off its PSTN, not before.
If the petition manages to get a bit of joined up thinking like this applied as a core principle then I think almost all of the PSTN related concerns go away, apart from the issue of whatever is needed to make landline connected alarm systems to work, which I suspect isn't that onerous a task (I'll happily bet that it's only some legacy system that need a copper pair to work anyway).
