Before recorded music the very best professional musician probably made five times as much as the one who was just barely able to reliably get work.
There’s an entire economics literature on these systems.
https://en.wikipedia.org/wiki/Tournament_theory
> Tournament theory is the theory in personnel economics used to describe certain situations where wage differences are based not on marginal productivity but instead upon relative differences between the individuals.
Where this doesn’t apply you get Baumol’s Cost Disease.
https://en.wikipedia.org/wiki/Baumol%27s_cost_disease
> Baumol's cost disease (or the Baumol effect) is the rise of salaries in jobs that have experienced no or low increase of labor productivity, in response to rising salaries in other jobs that have experienced higher (low or no) labor productivity growth.
> The rise of wages in jobs without productivity gains is from the requirement to compete for employees with jobs that have experienced gains and so can naturally pay higher salaries, ...
The explanation, or part of it, is a unified interconnected world market where even a tiny idea, well executed, can be incredibly well rewarded, since it scales across the economy of most of humanity.
Nobody really "constructed" it. It emerged.