This may seem overly pedantic (or ideological) to point out, but needing a license at all indicates the need to cater to at least one, major piece of centralization. Otherwise, yes, radio is a technology that still works.
My point may have had more "meat" to it, had the rumours been true that government ordered local cell service to be shut down in Boston. That rumour has since been debunked. But if government can shut down cell service, surely they could order some sort of ham radio shutdown as well? It doesn't mean that it would be easy to enforce, of course.
No. Point-to-point communications over RF will work (unless they're jamming a very large range of the spectrum, but then there's probably bigger problems.) When you hear about repeaters, they're used to repeat the low-powered handheld VHF/UHF signal (~5W max) to a stronger signal so more people can hear it. Repeaters are controlled and maintained by volunteers and not the government. They don't even allocate fequencies for repeaters. Registering is voluntary and it's controlled by local frequency coordinators who are again just volunteers.
The FCC and the government takes a very hands off approach to Amateur Radio. They'd rather have them be self-patrolled than get involved. the only time the FCC really gets involved is when people transmit out of amateur bands or when someone transmits without a license, but even in those cases it's usually amateurs that initiate the action.
> surely they could order some sort of ham radio shutdown as well?
Yes and no, only to the extent that some hams would respect such an order. The practicality of actually preventing someone, especially a ham from broadcasting ^H^H^H communicating via a radio is a dubious prospect.
My point may have had more "meat" to it, had the rumours been true that government ordered local cell service to be shut down in Boston. That rumour has since been debunked. But if government can shut down cell service, surely they could order some sort of ham radio shutdown as well? It doesn't mean that it would be easy to enforce, of course.