Games do a very impressive amount of work for graphics but there's a huge difference: a dropped/late graphics frame every now and then is not a big deal.

An audio glitch is very annoying by comparison, especially if the application is a live musical instrument or something like that. Even the choppy rocket motor sounds of Kerbal Space Program (caused by garbage collector pauses) are infuriating.

It's kind of the difference between soft and hard real time systems. Although most audio applications don't strictly qualify as hard real time (missing a deadline is as bad as a total failure) but failing a deadline is much worse than in graphics.