Years ago I made an attempt at a UI that wouldn't even require repositioning the phone in your hand: the buttons are literally under your thumb (if you forgive my shameless self-plug):
I remember this being a thing for sometime, years ago as you said - always found this approach very interesting and resulting in beautiful and diverse UIs.
Sadly this trend seems to have faded away together with the rejection of skeumorphism and the advent of "design systems" (eg component lib based design)
Back then the UIs and OSes were less set in stone. Nowadays we have two mobile UIs: iOS and Android (while there's also the gesture-based SailfishOS [1]). Just like everyone's a Qwerty user, which isn't necessarily the most efficient, even on mobile (example [2]). Problem is, you can only deviate so much from the defaults/standards.
No, not everyone is a QWERTY user.
French are AZERTY[1], we are 70 millions. There is a really small fraction of the population able to type on QWERTY.
Germans are QWERTZ, they are 86 millions.
Scandinavians have their own QWERTY variation, where a lot of symbols are mapped differently.
There is a whole world outside there, you know ? :)
I agree with you on the point that those are not the most efficient layout nowadays though.
Even the UK keyboard can drive you nuts if you are an engineer and you are used to the US one. The Enter key has a different shape, the backtick and the backslash are placed differently.
Interestingly, such UI (well done, but seen such before) challenges the whole size of the smartphone as we know it, akin to a gaming keypad [1] challenging a keyboard.
If you want to take it a step further you can look into something such as Azeron[1], I've ordered one myself. But prooduction time is quite long (3 months). So I haven't experienced it myself, ordered it because of RSI issues.
https://apps.apple.com/us/app/futurecalc-futuristic-calculat...