Image credit: My Sari-sari Store
Replying to both of Sydney's comments:
The population IS growing - but the fertility is dropping. Metro Manila's population growth is driven by both in-migration (transfer from villages to cities) and birth rate (which is dropping but is still above the replenishment rate in the neighboring regions).
This is consistent with global trends - by 2007, the world will reach a tipping point where more than 50% of the world's population will live in cities. OECD countries reached that tipping point early in the 70's. By the 2000 census, some 48.05% of the country's population was already living in urbanized areas.
Metro Manila and the expanded region will continue to grow population wise, but the fertility rates will continue to drop as the region continues to urbanize. Drops in fertility rates mean parents will have more resources to provide their children, and more time for work. In other countries this trend has been accompanied by increases in productivity and in entrepreneurial activity.
That being said, the time horizon for the effect on Metro Manila of the confluence - a larger urban population nationwide (happening soon); and the drop below replenishment rate (not sure when but the numbers are trending) -is probably 20-30 years (about a generation and a half).
Knowing what's coming over the horizon means we have to consider these effects as we envision scenarios for the future of Metro Manila.