> I think that is very undertandable given the memory footprint of
> the original device which ran in what, 128K of memory?
Ah, that explains it. One can probably still fit an MS-DOS-like OS in such space - but that won't leave enough room for user applications and MS-DOS programs had to write their own user interface, because the only one provided by the OS was a string output.
I've never seen a PalmOS device that had less than 2 Mb memory myself - but I guess lots of things have been "set in stone" for the early, limited devices and couldn't be changed later.