I think this is the game as well. Companies want to minimize risk for new hires, so would rather hire someone at $X and get 2-3 years out of them than hire someone at $2X and hope they get twice the value out of them before they retire or call time on their bullshit.

A small % of new hires (in their 20s and 30s) will stick around for >10 years, and the value you get then from years of incremental pay raises is huge. Those people are comfortable and don't know their market value or are too afraid to go and get it.