Some smartphones are locked down by their vendors. There's plenty of options to get full root access on something that's for all intents and purposes a smartphone, especially if you don't particularly care about warranty and/or keeping commerical apps functional.

I can host a wifi router and a Raspberry Pi with a web server that then connect to my phone regardless of OS and now I can run anything remotely. You cannot lock down any OS that has a browser and wifi. I don't need root, just under $50 worth of equipment.

It is trivial to get an older, unlocked cell phone that you can root. You then have a device equally or more powerful than a Raspberry Pi with built-in radios.

Smartphones need to remove their agnostic USB-C power source, otherwise nefarious parties will use it to power a radio jammer!

Pretty soon we'll all be texting each other on tin cans tied together with string. Until one of the cops trips over our cables.