A fascinating premise, and matches what I saw as an engineering director. The best just get bored and move on.
I think many teams are unaware how much extra value is possible by retaining existing employees vs hiring new ones. Each year I'd try to make sure I was "making them an offer they couldn't refuse" with new interesting challenges, new tech, plenty of personal research time, as much pay increase as I could possibly give, etc. A lot of engineering managers think that it's no big deal to just hire new staff, but even going from average turnover of two years to three years is an massive improvement.
I think many teams are unaware how much extra value is possible by retaining existing employees vs hiring new ones. Each year I'd try to make sure I was "making them an offer they couldn't refuse" with new interesting challenges, new tech, plenty of personal research time, as much pay increase as I could possibly give, etc. A lot of engineering managers think that it's no big deal to just hire new staff, but even going from average turnover of two years to three years is an massive improvement.