I've lived in areas where Comcast stayed up during long outages and areas where it didn't. Not sure about FTTN, but I don't think consumer broadband services are required to stay up during an outage like copper phone service is.

Not really, under an area blackout the fiberoptic transmitters will stop working, so you won't be able to reach other areas/nodes even if your equipment has UPS power.

But, in general, the idea of a UPS is to provide enough supply to allow for an orderly shutdown, preventing equipment damage or data loss. Its not meant for long term operations.

For infrastructure and other critical applications, the UPS is designed to give you enough time to go start the diesel generator, and continue the operations.

As a bonus, some UPS have filters to ensure that delicate electronics get a nice, clean power wave. This is usually the case in UPS for data centres.

Btw, how are you liking down under's "revolutionary" idea of Fibre + Copper? Is it as bad as it sounds?

For me it does work that way. We have fiber as well. There’s a big box for our block, which connects all homes to individual fiber lines. The next active part is apparently some kilometers away, so even a larger outage for our area might leave my internet up and running. Had it happen twice this year, and still could use the internet fine.