You could but it would be an utter pain in the ass and might not work 100% as it was before it broke because the thickness of the wires are different and USB isn’t just 1. It’s 3 and they’re so thin, you’d need to braid them together.

If the plug broke, you couldn’t replace the audio’s connector with a USB connector.

Unless the audio device is also USB. Then it shouldn’t be much issue; though they may not be color coded with the insulation on the inside.