Matthews is paid fairly, Marner is overpaid.
You can speculate all you want, but it doesn't mean you are right.
It is just as likely that they take a discount as they don't.
Public knowledge would lead me to believe that at the very least Marner was probably not happy with Babcock, could that have lead to salary demands?
Could the priorities of someone in their early 20's vs someone in their late 20's change?
Putting a blanket statement on a player's personality without any context is kind of crazy to me, but, speculate away.