That's true. If Poland, Russia and Italy qualify (assuming Serbia won't) through world Cup, Slovakia, Slovenia and Belguim will play in Sofia. In that case the teams from Europe occupaing the top places in world ranking will also have chances at the world qualies. These will be France, Czech and Spain.
You forget the fact that Italy is the host of one of these tournaments. if they qualify, FIVB has to find another host, maybe another European country, maybe not !