Thanks for your post. I understand what you mean I just don't think It's as successful as My way, but hey you have your ways and I have mine. Maybe i just feel like Keeping players for longer but either way works. Of course if you ever want to get to the really high leagues don't you think you have to get younger players and train with them rather then switching off every 2 or 3 seasons?
if you train all your player you didn't make it to the top leagues, because you should focus on a type of trainee(like Guards and C). And yes you could later switch your training regime and hold your old trainees, but when you are fit for the future your old trainees are probadly overpowered for the "now" which isn't good either. And when you stop training them at a reasonable quality, you need to replace them in two season because they are to weak for your new targets.
Try to have young players for their skill level, you are training but also don't hesitate to replace your other players and don't be afraid of older guys when they fit(the skilldowns are slow, and i think you loose more value betwen 24 till 26 then betwen 30 and 32 in totals for players of the same quality or at least the difference isn't that big)