Hi, Western.  "...an opportunity to be seized."  Sounds good. But if say, 30% or more of the population is over 65?  I'd say that qualifies as more of a "challenge" than "opportunity."  

Talk to folks in Japan. 
"Japan running low on workers as proportion of over-65s hits record levels ...People aged 65 or over make up a record 26.7% of Japan’s population ... according 2015 census data released by the internal affairs ministry – an increase of 3.7 percentage points since ... 2010."

That's half the "challenge."  Here's the other half: "the number of under-15s stands at 15.86 million – a record low of 12.7% of the total population, and a 0.5 percentage point decline from five years ago."
(Source: the Guardian, June 30 2016)

So, let's compromise.  Instead of a "shrinking" population, how 'bout one that's...constant? You OK with that?