It's really interesting when you think about that.

In the video world, we've had an arms race all throughout the last 25 years for the lowest possible file size at the best possible quality, with new codecs and containers constantly coming in and out of favour. Hardware playback has always been spotty at best, with little guarantee you'll get a file to play on any device in particular.

Meanwhile I could rip a CD and put it on even my first-generation MP3 player from the year 1999, and it would work. A blessing we rather take for granted.

I guess there just hasn't been sufficient pressure to toss MP3 out completely. From an evolutionary perspective, just like the horseshoe crab, it is "good enough" and so it endures.