It doesn’t and can’t exist, because the networks keep changing. You could have a 2005 phone that still is perfectly solid, but it’s a 2g phone and the networks now are all 4g and 5g.
Indeed the amount of lifetime you get out of a phone depends on what you need. I don’t actually use a smartphone as a phone. My phone has no SIM chip inserted. Wi-Fi is not getting outpaced as quickly. If you have sufficient control over your device, you can reverse tether as well.
This is how my old AOS 5 device connects (2 ways):
① AOS 5 → Wi-Fi → router w/usb port → USB mobile broadband stick → LTE(4g)
② AOS 5 → USB 2 reverse tethered → 16 year old laptop → router w/usb port → USB mobile broadband stick → LTE(4g)
My AOS 2 phone (from ~2009ish?) can also still connect via method ① but I have no use for putting it online.
What I care about is the phone-laptop connection so I can side-load f-droid apps, OSMand in particular. I will always be able to hack together a hotspot to update the OSMand maps.
and the networks now are all 4g and 5g.
You may have just helped solve a mystery for me. I was using an HSDPA stick to connect 2 yrs ago. Then one day I suddenly had no internet. Had to scramble to get another mobile broadband stick, which happened to be LTE – which worked. I bitched to the carrier. I thought maybe they pushed a faulty baseband update to my hardware and broke it. They claimed my modem just died. I thought no fucking way does a simple solid state USB device like that just croak. Maybe they pulled the plug on 3g and didn’t inform anyone.
(update) Nope… Just checked and it was this year that they pulled the plug on 3g… just last month for one carrier. So my mystery is still unsolved. Though I don’t suppose it matters… what good is a 3g modem now? I wonder if there are any hacks to get a 3g modem talking to a self-hosted fake tower.
The old laptop is the same one I use for all computing. So using an SBC would just add to the energy consumption.
But an SBC could be interesting anyway because there could be moments when I would want a phone to connect without the laptop dependency. So I would be interested in hearing how it works. Does the SBC also charge the phone over USB? Does the reverse tethering software exist that can run on an SBC? It would be cool to have this configuration:
phone → USB → SBC → ethernet → router…
Especially cool if the SBC could run Tor and proxy all traffic over Tor (though I suppose that job would best be served by the router).