I keep getting prompts advising me to download freeware. Sound files are traditionally large affairs.
Modems are small bottlenecks.
So listening to a soundfile several years ago while it downloaded was not really an option. The problem is, MP3s are still too large to stream down a modem. Streaming audio, therefore, takes this compression a step further. And with streamed media, this lossy nature is much more noticeable. Still, it is a price worth paying for the massive reductions in file sizes.