I used to have an extremely cheap phone plan that had 500MB data, then 64kbps for the rest of the month.

You'd be surprised how far you can get with that. IRC works just fine (as long as you use Quassel w/ Quasseldroid), HN works well, so does reddit (via redreader). RSS readers and wikipedia work as well, and for general web browsing you can set up a readability proxy (basically Firefox' Reader Mode, but server-side). And of course email works really well, too.

Been there, done that, and all without the benefit of a home Internet connection. I also created a couple of scripts that I could run on my desktop computer to install new software or update my operating system. After running the scripts on my computer, I would wander over to the library with nothing more than my phone to download the packages along with grabbing some videos to watch offline.

The issue isn't really living with 500 MB/month of data. For most people, it will simply be knowing that you can do that. The next issue they will face is having the technical ability to actually do so. Then, once you've done all of that, the question will remain: will they be interested in the stripped down Internet. A lot of us who frequent HN may be since the results will still reflect our interests. There are people on IRC who we would want to talk to. There is a slant towards tech sites with RSS. And so on. That isn't going to be reflected in sites targeted at a general audience.

Sure, me and you and everyone here can open a shell connection and do everything with text and it'll work great on 64kbps.

Some of these guys have been locked up for 40 years straight. They're not doing all that extra stuff. They want to go on Indeed or Monster or YouTube. One job site I had to load on my desktop to find out why it wasn't working for them, only to discover the pages had a 250MB payload of random crap downloading, including videos.

The COTS solution for some web browsing is Opera Mini, which may still work? It also uses a proxy to prerender and compress websites, and worked ok at 2G speeds last I used it. It used to work well as a java applet and made the wider internet functional on feature phones. Very solid software.

But as a practical matter, what people rely on phones for are services that are app-based. Good luck completing a Venmo transaction or any amount of banking.