My company has this tendency to hire externally open positions.
They tell the old employee with experience to train them instead of promoting the old experienced staff.
What could be the reason?
Why would a company hire someone from outside rather than promoting internally?
Here are some reasons why a company would chose to hire externally instead:
My stance is that a company should try to promote from within wherever reasonable, because employees tend to stay with companies where they can grow their careers too.
Flip side: I have three times been in a position where person was promoted internally and went from being a peer to being my boss. In all 3 cases I lost a good friend. This can be hard on both the former peers and on the new boss.
I think this is more likely in a tightly knit team environment. It can be avoided too if there is the right training for the new boss, both ahead of his move, and after.
(In my case it was staff at a boarding school. Everyone does everything, and during the school term you don't have a life outside the school.)