The airport can easily increase traffic and passenger volumes over the coming years, just look at T2 after midday, it's dead. Upon route negotiations or announcements the airport often adjust things accordingly, such as reconfiguration of stands (Remote cargo stands for Cathay 748, various changes for TOM 788s, T3 re-shuffle to accommodate FR).
However, the airport aren't going to throw tens/hundreds of thousands down the pan for those few nights a year we get diverts, it isn't financially viable. In an ideal world we'd have endless amounts of staff and space to deal with every divert you throw at us but no airport in the world is going to be like that
