Your question is quite tough but I try to give some suggestions and let's debate if you think l'm not on point. First, l would be happy you sack an employee who like his or the organization but not too skillfull. Don't train them much too, just let them know they are important and give them the positions their skills match.
And on the other hand, business men are always very fast and smart when it comes to investment on their employees especially. So if you know a young employee is having a lot of potentials and would mean a lot for your business in tomorrow, don't fear to invest in such employee because he will surely send your business to the top when he himself realizes that you are spending much on him to make his future bright. But also remember there are some few cases that these young employees can disappoint you after such investment on them when they find better places, but those few ones are the people that aren't greatful in life so it's always normal.