Even as of recent years Kane is still one of the leading goal scorers on the team. He has reached his thousandth NHL point, as well as matched his career high of assists, 66, all within the past few seasons. Much of that could be attributed to his linemen Debrincat as left wing and Strome as center. The vast majority of goals made throughout the season have come from two of the three working together during any given game. By removing Kane from the lineup it could impact the playing potential of his other two line mates. Therefore impacting the performance of the team as a whole.
The fear that losing Kane could be seen as a rebuilding strategy to help get younger players on the team, however if it's not broken then don't change it, is an outlook that should be taken. While it is common to see a players playing ability go down from age, that is not the case with Kane. With him still being a quality player, he could serve as a great teammate for the youngsters to look up to as they enter the league. Given his experience being on a team at their highest and lowest points, giving him the advantage of knowing how to react through each. Whereas if the team lacks that diversity there could be a lack of leadership in driving them in the right direction.
When the time comes Kane will likely be a hall of famer, with a hell of a career, however he's not history yet.