Football clubs are in for business. They don't tend to keep a player for that long when they have feel he is no longer useful for them and they have find a replacement for that same player.
Lewandowski has given all his best for Barcelona team, his prime time has passed because of age is not on his side again as the league competition is becoming tough day by day. He needs to be let go, so that another player would take his position. At least he will be remembered as ones a Barcelona player
Exactly, no matter how influential a player is, once they see that your are not more useful to them, they will sell you and sign another player to replace you with immediate effect.
When a player is getting old, the team will start to look for his replacement so that when the player can no longer perform well, they will use the other one to replace him, and once the player is aged, they are always careful with his contract extensions, they only offer them shorter contracts because they might not serve them that much.
Some people are saying that Barcelona don’t need a striker because of Lewandowski, they feel that he can still serve them for long and I said that they can’t keep relying on him because he is aged and has performed to his peak already, he need to be replaced that is why they need to sign new players on their position.