You are correct...to an extent.
But the key is, does he really wants to stay here ? We dont want to sell our best players but at same time, we should not keep a player who doesnt want to stay.
Romero is not a bad apple...in a world cup next summer, how confident are we that Romero is going to give his all or take it easy and not go that extra to play for us and protect himself for country ? In past, numerous times, he has done this...to put country first over club.
I would love to keep Romero and make him even club captain, IF he signs a new deal. But if he says no or drags his feet, its better to sell him now and get a option who will commit 100% for club.
Ideally if we sell Romero for 50m or 60m, I hope we go get a Tapsoba