Just this week I was looking for a portable music player, and I was rather frustrated about what's available. The cheap models suffer from various issues including unresponsive buttons and according to the reviews e.g. Sony's cheaper devices significantly degraded in quality with prices staying the same.
The next price range upwards has touchscreens, and either iOS, Android, or a proprietary OS in a rather mediocre quality. Also battery life tends to be on the shorter side thanks to those things now running a smartphone OS just so they can play music and run Spotify.
Then there are the super expensive devices, the only noteworthy differences being analog volume knobs, nicer smartphone CPUs and nicer sound. Still touchscreens and Android everywhere.
If Apple announced an iPod with clickwheel, integrated Apple Music/Spotify streaming and nice battery life they'd punch a hole into the competition. But realistically the remaining market is probably too small for them to bother.
