Ask HN: What if the internet goes down? What's plan B?

Given the Covid-19 situation, what if the internet goes down? Behind the servers and infrastructure are real people. Sure, many of them are working remotely now, but many tech places have shut shop. I'm wondering, what if the internet goes down? Is there something out there, peer to peer that the common people can afford - to either buy or build, that will allow them to communicate peer to peer, without the internet? I was thinking of maybe FM transmitters. Those are pretty cheap. And almost everyone has in some way, access to an FM radio. So they can in the very least receive information. But, what are our options for duplex communication?

P.S - this is not to induce panic, or to promote some sort of conspiracy theory, I'm genuinely interested to know the technological possibilities that we can use to help humanity. This is a technical forum after, all.