From the other side of the curtain, most companies have "salary bands" that they apply semi-uniformly, i.e., as a "junior developer" you can make from X1-10% to

From the other side of the curtain, most companies have "salary bands" that they apply semi-uniformly, i.e., as a "junior developer" you can make from X1-10% to X1+10%, as a "senior developer" you can make from X2-10% to X2+10%, and as a "project manager" you can make from X3-10% to X3+10%. The invisible hand of the market will lead prople to companies with the highest value for X2, which are usually also those where the productivity (i.e. contribution to company revenue) per person is highest.