In my experience (21 years, decent but far from astounding engineer) you you keep going up, maybe more slowly. I think the statistic is skewed due to two thing

In my experience (21 years, decent but far from astounding engineer) you you keep going up, maybe more slowly. I think the statistic is skewed due to two things. First, high earners at 15 years moving off into management, moving into more fulfilling jobs, or retiring early, pulling their high salaries from the average. Second, other devs with 15 years moving from outside FAANGM to FAANGM, getting a pay bump for themselves but bringing down the FAANGM 15+ averages.