Or is it duelling specialties?
Growth is good. Being stretched and challenged is good. But sometimes we can be pushed into something that is actually more of a shift than growth.
If someone is an excellent server at a restaurant - they make good money from tips, their customers are happy and ask for them by name, and the restaurant makes more money due to their upselling skills. So what's the best course of action? Promote them to managing the servers or to managing the entire restaurant? When do those skills translate to management and when are we taking someone out of a win-win-win situation and changing it to one where everyone loses?
If someone is a good programmer, does that automatically mean we should promote them to be a project manager or product manager as a reward? What if they don't like the new job, or worse yet, what if they are bad at it?
Is the best cellist in the orchestra a perfect fit to replace the conductor when they retire? Or did we just lose the best cellist in the orchestra and gain a mediocre conductor?
Is a faculty member who is a good researcher by default also a good teacher? Should we promote the best teacher to department head or dean in the name of personal growth?
Managing people, operations, and projects well is a skill. It is its own specialty. You don't have to be a good programmer to specialize in managing programmers or a good cellist to be able to conduct cellists. A project manager may focus on a certain industry, but at the end of the day a good PM should be able to manage any project.
The biggest issue it seems with most "good" managers is that when they see people under them who are good at what they do, they want to promote them to be a manager just like them. It's time to flip the conventional wisdom on its head and start rewarding people for being good at what they do and helping them achieve true growth in their lane rather than convincing them that it is a reward to shift into a completely different lane.