I think Bayern's management is also very aware of this, they really need a single striker like Lewandowski and in fact Kane is a suitable candidate, but does Bayern not have other candidates who might have the potential to become the next Lewandowski, there must be a lot another, less exposed striker who could be a substitute for Lewandowski.
Sadio Mane has pretty much damaged his career by joining Bayern Munich. Because it was at Liverpool that the game performed incredibly well and his career progressed tremendously. But his performance at Bayern Munich has not been noticeable so far.
Most people do not realize this but Klopp makes these players better, sure they are good players but he utilizes them to the peak point and that is why he is such a great manager, sure he wasn't that great this season so it is not going to be the same, but he definitely utilized Mane amazingly until he left.
This meant that even though he is a good player, nobody could have made him as good and that is exactly what happened, at Bayern he ended up maybe getting paid more, which I am not even sure about, but he didn't really get to play that great. Now let's see where he leaves, because I can't see him staying here and he will probably go to a smaller team and get paid worse, if he stayed at Liverpool both him and the team could had a better season.