What kind of organization culture do you have where someone leaving after two years causes an "amount of pain" and you have to spend considerable resources on-b

What kind of organization culture do you have where someone leaving after two years causes an "amount of pain" and you have to spend considerable resources on-boarding new hires? That sounds like a deeper problem to me. I tend to work pretty short stints at places, but in the vast majority of cases am shipping things to prod the first week or so and building and releasing revenue generating products in the first 6 months. Most of the places I've left, even after a short tenure, are continuing the work I started just fine and generally get lasting value from a even a year of my time. With few exceptions, most of the teams I've left are sad to see me go, but that doesn't diminish the befit my time there has provided. On the other hand most of the people I know that have worked 7+ years at a place aren't particularly engaged in the products and certainly aren't keeping up with major industry trends/changes/etc, and generally just go to work each morning without leaving much of an impact. Even at places like Google, most of the 10+ year people (with some notable exceptions) are the "rest and vest" types.