Yeah, although at the same time, I reckon early on is the best time to train the oldies. It'll probably take you a while before you can afford a decent trainee worth giving 3 or 4 nets to, so you can compensate by polishing your squad.
One of the first things I did, I took a feeble/respectable/feeble who was a part of my squad and improved his concentration to respectable. I later improved his stamina. It doesn't take that long on the older ones and in most cases a player like that will be with you for several seasons, probably averaging over 50.
I later did a similar thing to a respectable bowler, but I gave him bat/bowl/field/keep mainly to see the effects. This produced an even better effect than what I was looking for, as he was high respectable and popped to proficient. Obviously, in practice it's not a leap in performance, but it is good to find your player is better than you thought, at a time when you probably don't understand wage calculation.
Considering the market as it is, even competent players in the initial squad are worth this sort of treatment.