Replaceable which screwed up the company and replaceable and continue same productivity are 2 different thing. The former is real and happened for millenia, the later only exist in CEO's and Wallstreet mind. When I buy stock I look out for changes to their staff (some engineers and mid managers are worth keep track of to indicate companies growth projection). Warren also famously did so. You can investigate Intel and Boeing staff movements over the years...I can guarantee you 300% their talented staff left and hence gameover for them.