I wish this happened more often in companies. Unfortunately I usually see the following happen. A mid-level developer, let's call him Dave, becomes a critical

I wish this happened more often in companies. Unfortunately I usually see the following happen. A mid-level developer, let's call him Dave, becomes a critical employee after a few years with the company. He silently become "senior" without anyone really asking him to. Other developers notice this and often come to him for help. Management, however, doesn't notice, because nobody in management is exposed to Dave's actual contributions to the team. All they see are completion metrics – story points, etc. – and a project moving forward. Dave is too humble to point out that he did 80% of the work, and he doesn't have regular meetings with his supervisor anyway, so the subject would never come up. After a few years with the company, Dave gets bored and finds another job. The company now has to pay recruiting costs and the ramp-up time that comes with a new person on the team. Dave, meanwhile, gets what he wanted – a promotion, and a higher pay check. The company could have saved money by giving Dave a 20% raise and a promotion (even a nominal promotion, to make him feel valued) but the management structure wasn't there. This is how it normally goes, and this is exactly why there is such a short length of tenure in the tech industry compared to other industries.