I think Nintendo only wanted to show proof of concept, that the computer part of Family Computer really had bearing. They never intended to become a full fledged computer manufacturer, so many else in Japan were doing that in various price ranges and they already had a best selling video game console. Besides, aren't FDS mostly read only or can games save progress to the disks?
early manufactured had the ability for full read/ write(tho nothing supported it )
pretty quick they changed the hardware so it would only write to a small section of the disk for saves
its pretty simple to make the early drives able to write new disks , the newer drives require a mod chip of sorts to make them be able to make new disks
as for op you can still save and run programs but not from disk you need a tape drive
Edited by discgolfer72, Sat Apr 14, 2018 12:53 PM.