I think you're pointing at the fact that there are only three kinds of cones, whereas the ear has … well honesty I'm not sure how many different kinds of hair cell there are. apparently [16,000](https://www.nih.gov/news-events/nih-research-matters/hearing...)!
the eyes are much better at directionality though; probably some kind of trade-off going on there.
Well it's position vs frequency, so a tradeoff is forced by the Heisenberg uncertainty principle. I don't know if either system is actually reaching this limit though.
I thought about that, but you could just cram more cells to get higher resolution. Reflecting a bit more, hair cells vary by length, whereas each new cone requires a unique protein, so I'd expect hearing to respond to more easily to evolutionary pressures.
the eyes are much better at directionality though; probably some kind of trade-off going on there.