Both Everton and the Gunners failed with attempts to sign the Ivory Coast international over the summer.
"If a player wants to go enough and is desperate enough to leave then it's possibly not in your best interests to try and keep him because you then have a player who doesn't want to be there," he told 888Sport.
"Not that Wilf wants to let the club down in any way. He loves Crystal Palace. He just wants a chance to further his career and go to potentially a bigger club like Arsenal. That's the type of club he needs to move to. He needs a club that is challenging for the Champions League because that's the standard that he's at.
"I don't see him lying down and not trying though. He doesn't strike me as that type of person. He cares enough about his own club and will give his all until he moves on.
"Premier League club's finances are getting stronger and stronger and all that's going to do is push prices up but there must be a price eventually that a selling club will take."