Every empowered manager's goal should be to leave their employees better than the way they found them. Not just a little better, but so valuable that you can no longer pay them what they're worth.
If you constantly nurture entry-level employees to become so marketable in the workforce they take the talents you nurtured to another employer, perhaps even your competitor, you've done something profound. You've made someone more valuable.
The real beauty of creating employees you can no longer afford is they are not likely to leave you to work for someone who might parasitize them, dispirit them, and empty them in exchange for a better wage. (If they do, something else about working for you needs fixing.)
Make your employees marketable and they will either remain with you forever at less than market value for the sheer joy of working for someone who invests in them, or leave to seek a better lot in life. Either way, you win.
The alternative is to make them mediocre and unmarketable. How rewarding is that?