No, you know what? Go on, do it. Try to tax the internet away from us, slowly. If you don't think there's tens, maybe hundreds of thousands of people who wouldn't devote their lives to seeding the next free internet within a year*, tops, then you're a fucking idiot. No, actually, it's already out there, the need for it just hasn't hit critical mass yet. Take the 'net away completely, and you will sow a near-instantaneous revolution of some sort. Good luck. *Edit: Obviously there exists an entire gradient of severity that necessitates a variety of responses. I think that some people are currently working to determine the best course of "business-based" actions (hint: it's gradual) that may eventually rob us of our lion's share of online autonomy and anonymity.
I think you could encode some ham radio frequencies, but passing the cypher between cities would require someone making the trek. Not sure that this would be sustainable, though. Also, all smartphones have an FM chip, not really sure how hard you could drive it, I'd imagine it just acts like a receiver.
https://en.wikipedia.org/wiki/Darknet If we keep losing the right to anonymity and to freely traffic around the internet, we'll build an increasing number of applications for peer-to-peer networks centered around the mobile device, using wifi. That's what I'd do, at least. If anybody can naysay that or come up with something better, I'm all ears.