My prediction is that they will be by the next generation. In Guardians of the Galaxy for example, the obsolete-but-nostalgic format is the cassette tape and Walkman. The CD and Discman will fulfill that role in 20 years, if not sooner.

I think the problem with Discman is they didn't stay fashionable for as long. My first Walkman was my dad's old one from high school. And they didn't really fade completely until the 2000s.

The early model of Discman skipped really bad, so anyone listening to music while doing some physical activity mostly stuck with Walkman. It wasn't until memory was cheap enough that they could have decent buffers that people started using CD players more, but not long after that, MP3 players started to become popular.

CDs were more of a car thing. Everyone at my high school had those big ass books of CDs in their cars, even if they all also Rios for personal listening. Then the big 20GB HDD-based MP3 players came out and that's what everyone had.