Bayern Munich did not have any option than to keep him for more than three seasons because they don't have his replacement, if Bayern Munich did not give him a new contract how would they get a good striker that play like Harry Kane? Harry Kane is not just a striker but an engine that never give up when he is playing, he has proven himself in the premier league and many tournaments, having him and build a team around him is the best way for a club to win a trophy, Bayern Munich know why they want to keep him for a long time, he is a player that any top club will want to have in their team.
Harry Kane is a very talented player. Unfortunately he spent most of his career in a Premier League team where he failed to win any trophies. With the move to Bayern Munich this changed. Bayern Munich is a team that tends to win a lot and often. Consequently, Harry Kane is good for the team, just as the team is good for Harry Kane.
In the Premier League the competition is very tight he is at Tottenham already working hard, but I don't think he has a solid team to help him get a lot of chances on the pitch and keep winning, even when Tottenham don't get a good position in the team, Harry Kane becomes one of the players who scores the most goals, even many people make statements that there is like a curse and the phrase legend without a trophy, but now it's different.
The contract at Bayern Munich until 2027 of course this must be extended, at least two additional years until the age of Harry Kane turns 35 which can be said to be still productive, here indeed Harry Kane gets many chances to get trophies for the last time of his career, and yes on the other hand for the Bayern Munich team itself the presence of Harry Kane's figure is very helpful in sharpening their central attacking line.