In our current job-hopping world, where you are lucky to even get 4 years from an employee, you can take someone from good to great, acceptable to good, or bad to acceptable in the time you work with them. Your investment should almost always be on the first two, especially because the last one is a much bigger investment of time and energy. Keep in mind many times what you're fighting is not just lack of experience or some other easily fixable thing, you're fighting personality traits the person has had for years, and will continue to have (to a lesser degree) even if you _do_ "fix" things.
It is one of my signals of inexperienced management that they believe they can/should take on this sort of challenge.
Yeah, ~10 years as a manager (and 30 in the industry) is not a lot of experience. But it's enough to know that "focus on the stars" mostly aims at making the managers life easier - anybody can manage a team of great performers.
Of course it's a judgment call. Some things, you cannot fix. But some things, you can, and the cost of doing so is much less than rehiring. Good management means making those judgment calls, not just saying "meh, I don't care about low performers, too much work".
Maybe, just maybe, that's a tiny part of the reason people on my team seem to stay longer than 4 years. Because we don't just treat them as disposable cogs.
I'd be happy to discuss over a beer. I don't believe there are any hard and fast rules in life, and I've tried to help people more than once in my career (currently I do it in a non-management capacity which is arguably harder). But I think we can agree some situations aren't going to be saved. Good management is knowing how hard to try and when to stop.
Always happy to discuss things over a beer. (Well, I'll have white wine, if you don't mind ;)
And yes, not every situation is salvageable. Alas. Knowing when to stop is why I'm in favor of having a defined process well before you come to the "change, or else" part. That prevents the sad effect that your bar shifts as you collect reports, just because you've got more things to do.
It is one of my signals of inexperienced management that they believe they can/should take on this sort of challenge.