One thing not taken into account in this discussion is the natural limitation of career growth. Everyone has a cap on their advancement. Some devs hit that cap after 4 years, some after ten. But a smaller and smaller percentage of employees are promoted to a higher level after the requisite amount of experience.
At Google and Microsoft there is very large percentage (~60%)of employees in the T4/SDEII bracket. This is the 2-5 year experience bracket. The percentage of employees in a level exponentially tapers off when compared against higher levels. This could be one explanation of the graph as presented.
At the companies you mention, the graph is accurate when plotted against population but incorrect when plotted against level.
Mid to higher levels see approx linear growth in salary and compensation until the top echelon. The compensation difference between two levels is approximately 10% the starting salary of a college hire. However, this highest levels including directors, tech managers and partners see clearly non-continuous bump in salary and equity (2-5x salary, 10-50x stock).
At Google and Microsoft there is very large percentage (~60%)of employees in the T4/SDEII bracket. This is the 2-5 year experience bracket. The percentage of employees in a level exponentially tapers off when compared against higher levels. This could be one explanation of the graph as presented.
At the companies you mention, the graph is accurate when plotted against population but incorrect when plotted against level.
Mid to higher levels see approx linear growth in salary and compensation until the top echelon. The compensation difference between two levels is approximately 10% the starting salary of a college hire. However, this highest levels including directors, tech managers and partners see clearly non-continuous bump in salary and equity (2-5x salary, 10-50x stock).