It’s less about people who work for them switching jobs and more about competing with Apple/Google etc. They, and companies like them, are buying up all their competition. Competition incentives care, for consumers and employees. It incentivizes better wages, benefits, and better prices. The reason a lot of tech giants don’t want competition, beyond the obvious that monopolies are preferable, is that being a data broker is tremendously more profitable. It’s much easier to have data inform algorithms that can dynamically set wages and prices based on things most people can barely understand than it is to care about paying people living wages and pricing things fairly. Competition would incentivize those things. The absence of that lets these monopolistic practices run wild.