25 years ago...

Manufacturers were smart enough to develop the 3.5" 'hard' floppy, as opposed to the partly open 5.25" 'soft' floppy. It became a universal hit partly due to being completely encased, no more fingerprints, dust or grit on the media surface.

For some abysmal reason, optical technologies never progressed this far, to a standardized encasement. And has held it back ever since.

And does this insanity date back to the very fact that LP records were not encased, and thus CD's followed this rule? So in effect the current optical technologies are still living the era of open reel tape, never having progressed to the standardized encasement of the C-cassette.