#1 Trophies
It all comes down to this, doesn’t it? For every player, the main incentive to play the game is winning. No player wants to lose. Yes, money is a big factor for a player to do what he does, but winning trophies is the ultimate dream for every player.
At Tottenham, Kane is enjoying the best period of his individual career. However, he has no trophies to show for it. It is for this reason why he added the clause of “winning” trophies with Spurs in order to be happy to stay.
Both Gareth Bale and Luka Modric moved to Madrid to win trophies—and win they did. For Kane, the same is the case as he would like to end his career as one of the most decorated players in the world. Currently, at Spurs, that is not happening—which is a cause of concern for both him and the club.
At Madrid, he has more chances to win trophies than he does at Spurs—and that is why he will move to the Bernabeu.