I would say the comparison with resolution for audio is how high in pitch we can hear, how low, to what degree of precision we can tell how loud something is, like if you raise the volume of a sound in increments what's the smallest increment you could perceive. For audio this basically comes down to bitrate and samplerate, and we maxed those out a long time ago.

In so far as number of sounds, it's just after a while it becomes a mess.

Like, imagine waves in a pool. If you have one wave, you can see it easily. You could mix a number of waves and still be able to tell which is which. But after a while, the water would just be a mess of noise.

When you listen to a record, every element sounds distinct, and clear, because the engineers mixing the music made sure if did that. Even just a few elements can really start clouding over things and making them intelligible.

Just like if you have one person talking that's easy, 2 people taking you could go back and forth and you know they are distinct voices. After a certain number of voices, it becomes noise. If you have enough noise, you won't notice an extra voice being added.