I spent many years deciding promotions at a big tech company, including for Sr managers. One thing we always looked into was were they growing the talent on th

I spent many years deciding promotions at a big tech company, including for Sr managers. One thing we always looked into was were they growing the talent on their teams, mentoring, growing skills, and getting people promoted. People understood this was one of the criteria for manager promotions, so they spent time on it (and documented it). Like any other job, people tend to respond to what they are told will be the evaluation criteria.