I think Bayern can find his use still for 3-4 more years in my opinion. He is a top striker and Bayern have invested a lot in order to get him. Naturally they will use him for a long term and they certainly have bought enough time with this also for finding a young striker filled in with good potential. I think in 2-3 years Bayern will start looking for next striker.
Bayern Munich have made the right choice when they sign Harry Kane from Tottenham Hotspur. It's very important for the Bavarians to sign a replacement for the top striker who created a vacuum space in the frontline, but now they don't have to worry any longer because the ultimate striker have become the best signingn for the club this season. Harry Kane have arrived and will enjoyed every best moments in Bayern Munich. Thomas Tuchel just have to restrategized his squad for the purpose to ensure they are fit enough to compete in major tournaments this season.