An economically optimal price is one that maximizes total profit.
If it's too high, fewer people will buy the product, which might reduce profit. If it's too low, the profit margin will be small in spite of lots of units sold.
It's subjective, but that doesn't make it nonexistent. I pay $10/mo. for Spotify. I'm happy with that. I think I get great value for that money spent. If someone came out with an $8/month streaming service, I'd scrutinize it fairly closely before contemplating switching.
If so, I'd mark that behavior as strange, and not actually evidence of the existence of a "fair price." There's no way this behavior is typical.
If what you're saying is that you'd assume a price lower than $10/month would have other, unseen problems, then:
1) You're not referring to a "fair price" but instead a believable price, which is a compromise between what you want to pay (which is nothing) and what you estimate to be the price of delivery, and the odds with that price in mind that what you receive will be adulterated/lower-quality than advertised.
2) How is $10/month fair? No wonder musicians don't make any money.
Yes, it does. Subjective assessments have no objective reality.
Subjective assessments drive political preferences and policy, to say nothing of human relations and experiences.
I don't think the prices on music were unfair before. No one has to have music, and there was no evidence that the prices were enforced by unfair practices. They were just higher than people wanted to pay.
But most people would say that Enron's manipulation of energy markets was quite unfair.
Copyright is the unfair practice at work here enforcing high prices for distribution of information, a service which can be provided at practically zero cost when not restrained by force.
The economically optimal price is the one that maximizes total value in the long run.
What value? Units sold/quantity of product? If so, should businesses operate at breakeven in the long run?
This is an interesting take, it is optimal for everyone, not just the producers. I agree that this would be the ideal scenario for society.
The problem is - how to arrive at it?
Profit sends a message that offering X instead of Y is more profitable - and therefore, better use of one's time.
How would you reduce/remove profit without destroying incentives to innovate or even pivot to new industries?