I mean I don't mind a good console app, but it's not like lemmy is mouse dependent by design, it's just that there hasn't been major demand for a console or desktop GUI with local storage. The APIs are wide open and pretty simple, so it wouldn't be hard to make one. Personally I don't think my post history is worth backing up locally, but I don't make a lot of big effort-posts I suppose, others who do would do well to back those things up (though lemmy does differ from mastodon somewhat in this regard I think).

Even Slack (I hate it but it's mandatory for work) barely has a functional terminal client, I had to modify the source code to get the one I found working without admin approval. Personally I'll take a desktop app with good keyboard compatibility over a text-only app generally, but this is largely because so many console apps lack functionality that their GUI counterparts have or are no longer maintained.

Times are changing. There's good and bad to it, smartphones are a really highly refined way of interacting with a huge variety of services, but that refined-ness also is part of what makes them addictive. Small screens and keyboards are relative, with the size of the average smartphone these days most people seem plenty happy with the screen sizes. And things like swipe typing make it quite quick for basic conversation, if a bit slower when you try to type a word the autocorrect doesn't know, etc.

Edit: I wonder if you could make a self-contained lemmy stack that acted as a single-user homeserver and client... That sounds like what you want, really. I don't know how well lemmy federation would tolerate it, and you'd probably have issues with images down the line since your local PC presumably doesn't have comparable uptime to a server, but it could be made to work, and with a reverse proxy it wouldn't be horribly unsafe privacy wise I don't thiiiink. if you just didn't accept image posts and used a cloud service for them or something it could be pretty slick/simple