Your answer might be the 'simplest' but, there is an alternative..
The club have, belatedly, offered him a contract because they don't want to lose out on the transfer fee.
Ross wants to stay and be a part of a successful Everton team, he's good enough and deserves it.
He thinks playing for Everton has served him well so far, he's played well for England (anybody reply with "he didn't get picked by".. the likes of Roy Hodgson, Sam Allardyce and Gareth Southgate, should lower their heads).
He thinks, by not signing the contract, he will get offered more and maybe RK will shut up and stop talking about him.
Everton and the players will know his stance, a path trodden so many times before and with the blessing of many a player.
Ross is the player he and many, many others think he is. The bottom line is that until it's a done deal, he's still an Everton player and hopefully, is until after RK (does a good short term job and moves on, which he will) goes.