To be honest, I don't think Elon Musk will help us having a computer that you own (so not owned by big corporations), and I think so because he already recommended Signal (wants your phone number, and it's also not decentralized like XMPP, so it died after his recommendation) and Bitcoin (not anonymous by default, unlike Monero). The only thing that can save us is, well, ourselves, trying to kill capitalism. That way, having "a computer that is designed largely to maximize the profits of the computer industry" won't be possible. About the anonymity networks, yes, most of them just overlay the clear net, and so they're easy to block, like it happened to Tor in Venezuela (clear net only).

I agree, meshnets like ZeroNet, RetroShare, Tor, IPFS, should be more popular. Maybe localized networks should too because you could, like you have given as an example, share data from your personal weather station.

About mesh-nets that have no direct connections, Freenet is the solution (and our hope) for that because, if I remember correctly, doesn't connect to the clear net (unless you choose to download its updates through the clear net, for some reason).

Also, I don't really think it's possible (or it's just me) to live without technology. Sure, you can limit its usage (like by not having home assistants or IoTs), and yes, technology is filled with privacy violations, manipulating algorithms, narrative control, but it's clear that life would be hard without search engines, web browsers, and communicators.

So, I think that as a TL;DR to this: the solution to having a computer you own (as well as other problems) is to kill capitalism.