So let's think one more step out. You're supposed to train your juniors so that you have seniors when everyone else is scrambling. But when everyone is scrambling, the biggest and most-funded/most-profitable companies will be offering a lot more money than you can afford to pay your now-senior devs. Now I suppose you think those former juniors would be so grateful that you trained them, that they would be loyal to your company and continue working for what you're paying them, right? ...right?