SYD just keeps on performing, growth is coming from the volume countrys. (These countrys have capacity to keep growing at high levels for a long time due to size of population and growing middle class.)
By the time Second airport opens IMO SYD can send away the low cost airlines and just service the growing legacy market where convenience is the priority rather than cost.
Reinvesting back into the business to handle more/forecasted growth.
Dividend growing faster than GDP!