I missed the basic era by a little but I always wonder why the BASIC roms never became the shell of the disk operating system when disks entered the pictured. Think analogous to the unix shell which is both the interactive command line and a scripting language. Get rid of the line numbers, add some directory access commands (list, mkdir, cd etc) and you would have a pretty good cli. but nobody appears to have done this. Instead you ended up with things cp/m and dos. fine enough I guess but their command interpreter sort of sucks in comparison to what basic could have brought to the table. And basic was already there.