> In the 90s everybody knew how a paper book worked
I hope that’s still the case!
It's hard to call this an example of "skeuomorphism". Those icons were introduced on physical buttons with a certain meaning that everybody had to learn. They have exactly the same meaning on software buttons; the interaction that people have with them now is the same interaction that everybody has always had with them.
This isn't a case of the software appealing to a visual metaphor that made non-metaphorical sense before the software. It was just as much of a metaphor originally as it is now. You might as well call the word "edit" a skeuomorphism in modern software because past software also had "edit" menus.
Right, that was my point. What does it matter what a diskette used to be? Unless something more obvious to convey storage/saving comes along, it’s hardly “crashing down” anytime soon.
Play and pause icons aren't skeuomorphic. They're symbolic. There is no point at which they were a reference to some phenomenon earlier than or other than themselves.
The double-pipe pause symbol originates on the video side, where pausing keeps displaying a freeze-frame image, and stopping does not. Audio players had pause long before (which just causes the drive wheel to un-grip the tape), but used a variety of different symbols.
> "[play] The meaning "to cause (a recording) to reproduce what is on it" is by 1903, probably from the "make music" sense." - https://www.etymonline.com/word/play