https://www.bloomberg.com/news/articles/2017-02-13/one-reason-staffers-quit-google-s-car-project-the-company-paid-them-so-much

Because the autonomous car project team members had less financial incentive to stay, they chose to leave. Some started their own autonomous car business. And others joined  other car business company.

It's safe to say that companies' employee compensation structure plays a role in employee retention.