I reckoned someone will say that.
Yes, you can continue to increase the size of the boat but as
with everything there is an optimal size you can grow until.
Singapore is a small country without much land, unlike countries
like Australia or Canada. You can grow up till a certain
point whereby the law of diminishing returns kicks in.
If you say you want to increase the population to 6 million to
make up for the aging population, what happens when these 6 million
starts aging? You import another few million and increase the
population to 10 milllion? And when these 10 million gets
old, you increase the population to 20 million? Get my drift
here?
There is an optimum size for everything.
Like the boat, you can build and improve it until it becomes the
size of an ocean liner.
Very impressive right?
But even the Titanic sank.
Yeah, not enough life boats for everybody. 
Dun worry, the last few days, i was given a tour of far end
changi, OMG!!! the reclaimed land was so huge that it can anytime
take over 4 big towns in the inland. So most probably, some of our
older folks may move there when it is fully developed.
Talking about diminishing, the govt too calculated to
factor it in their plans, the targeted population was pre
planned to increase to 6.5 millions in about one generation time,
as some will be migrating out and some who take here as stepping
stone only, the calculate population by 2030 will be around 5.5 to
6 millions which can last for another generation of about 50 years
before another generation come into place,..and that will last for
another 50 years to and so on. The govt also noted the replacement
of old ages and the longervility of life here, but then who cares
what happen in 100 years time. That is a century from now we are
talking about, whether there will be diminishing or
progressing thru some technology or increasing of land, no much of
us give a damn, cos by then, we long long become dust already. And
the LEE or PAP may not be in power liao.