I am sometimes jealous of those who sell domain names. There’s only one “example.com”. Scarcity is built in.
With logos, not so much. But scarcity is built into every endeavour where creativity is required. There is only one of you, right?
In art this is more pronounced. There is only one Dali. Only one Duchamp. Only one Matisse. No reason why this can’t be true in design. There is only one [_insert your name here_] and when you get to the point where people insist that YOU and no-one else create their logo, you can start charging what you are worth.
How do you get there?
I’m still working on it, but differentiation is 90% of the recipe. Balls make up most of the remaining 10%.