A great, detailed explanation of what you are seeing: https://blog.pragmaticengineer.com/software-engineering-sala... (and the other two parts of the series)

The most important point is that your compensation is far more sensitive to getting onto the next curve up than it is tied to your experience or your work at your current company.

This is why so many people say "Grind Leetcode, get into FAANG" as the goal in software engineering, because (at least until recently) being in FAANG even as a junior SWE pretty much guaranteed you were in the second or third curve, and once you were accepted into that curve you would generally find jobs in that same curve. With the way the software engineering job market has changed, I'm not sure that's true any more, but as recently as 2023 it was the rule of thumb.