Yeah I do wonder if statements like the above are something of a self-fulfilling prophecy.
If you don’t have a good touch by 24 it’s not going to happen. So if you have a bad touch at 25, coaches write a player off and stop paying attention, players realise this so don’t train so hard and go play social football.
Whereas if that rule of thumb didn’t exist, maybe coaches wouldn’t stop paying attention then late bloomers could keep working hard at their touch and improve to the point where they can play professionally.