- Poor conductor
- Hard which makes for reduced mating contact surface.
- Only used in audio
- Uneducated consumer
I am sure there are more reasons.
Current estimates are a leading edge semiconductor plant costs $10-20 Billion (that's 9 zeros). Even a large geometry analog fab is high 100's of millions. I.e. price is really no object. You will not find one rhodium plated connector in that plant.
