There are numerous possible answers to this question. People can start well, start poorly but do well in the long run, or get extremely lucky with the company they choose. For example, a person who graduates with the average salary of the batch is likely to be earning 4.5-5X their first-year package after ten years if they perform consistently and do not deviate from their growth path in any way. The ratios will obviously differ if you start at a lower or higher salary than the average.
Furthermore, switching companies for faster growth would provide you with a package similar to what a reasonably successful person who stays with the same company may receive.