When he signed that contract, he was a 23 year old winger who had one prolific season in front of goal in the best team in English history, and had come off a disappointing world cup.
Since he signed that contract, he's scored more goals for us than anyone else, having his best goalscoring season last year with 31 despite the team's stuggles, become a nailed on starter and regular goalscorer for England and is widely regarded as one of the best players in his position in the world, despite what some on here would have you believe.
He's clearly a more valuable asset to us now than he was then, and with inflation to consider as well, he's absolutely right to ask for a modest pay increase. He'll get it too.