[alexisread]

Apart from transputers mentioned already, there’s https://greenarrays.com/home/documents/g144apps.php

Both the hardware and the forth software.

APIs in a B2B style would likely be much more prevalent, less advertising (yay!) and less money in the internet so more like the original internet I guess.

GUIs like https://en.wikipedia.org/wiki/SymbOS

And https://en.wikipedia.org/wiki/Newton_OS

Show that we could have had quality desktops and mobile devices

[PostOnce]

I want to chime in on SymbOS, which I think is the perfect reply to the GP's curiosity.

https://www.symbos.org/shots.htm

This is what slow computers with a few hundred kB of RAM can do.

[nxobject]

The original Macintosh had similar specs as well – 128k with a 68k clocked at ~6-7 MHz. It helps that both platforms put a significant amount of OS code in ROM.