Cause they haven't been in another AFL system? It's far easier to teach someone who is a blank slate vs someone who has been doing it a certain way for eight years.
Mayes would probably be exactly like 2018 Polec at this point - he'll look fantastic because everyone else is doing their role, but he won't be playing team football. He needs to learn when it's time to push forward and when it's his turn to drop back and defend. I have full faith that he will.
How do you know how smart Sam Mayes is? I realise you think football is rocket science, but how do you know he's not a super nerd?
Its actually not rocket science, most footballers can even do it