You think the companies that do rigorous performance reviews, regularly fire people for performance reasons from executives down to interns, and provide insanel

You think the companies that do rigorous performance reviews, regularly fire people for performance reasons from executives down to interns, and provide insanely lucrative compensation packages don't care about 'productivity', and instead just choose to invest in more tangible results? Why would these companies we're talking about spend so much money compensating employees and firing bad ones if it doesn't matter?