Mbappe has been linked with Real Madrid since the beginning of last season but until now, Mbappe still seems difficult to leave from PSG because maybe PSG also still needs him or something else.
Obviously PSG want a lot of money. PSG certainly do not want Mbappe to leave on a free. The price makes big clubs doubtful. So if Mbappe doesn't leave then he must be willing to sign a new contract extension. While Mbappe is reluctant to do so.
Maybe if the price is still reasonable, there will be many clubs competing to have him. But with a price benchmark it might be a little difficult. Even when compared to Ronaldo when he came, I prefer his style of play and Mbappe is still below his level.