Sorry for a late reply. In most companies outside the US nobody, not even the CEO, makes 10x the income of an average low-performing engineer. A high performer has a chance of getting a respectable salary only by rising to CTO or similar roles, which obviously require skills other than just project contribution.
There is literally zero chance a high performer would get even 3x salary compared to their peers. Those pay ranks simply do not exist.
The compensation scheme at companies that employ them.
>What generates that gap in pay?
All companies are different but it's typical a difference in grade or rank.