It depends on the industry. In any industry not undergoing disruption, having the long-time employees probably is a good thing. They know how to execute process

It depends on the industry. In any industry not undergoing disruption, having the long-time employees probably is a good thing. They know how to execute processes well, and know the detailed ins and outs when any random thing goes wrong. They also know the 10 or 50 other people to call when help is needed. When any of those individuals leave, you have to hope they have a successor who's been handed the core knowledge.