You're assuming at least two things that I disagree with.
First about behavior in old age. I'm pretty sure the majority of adults today don't want to live and think like their grandparents, so we can't say "less" anything. The circumstances are definitely changing enough that we already know it will be different.
The population decline is not happening in huge step changes. "About to bite us" is definitely hyperbole.
No, it will simply be a slow and steady increase of pressure on the working age population: taxes, retirement age delayed further and further, "everyone must work", etc...
First about behavior in old age. I'm pretty sure the majority of adults today don't want to live and think like their grandparents, so we can't say "less" anything. The circumstances are definitely changing enough that we already know it will be different.
The population decline is not happening in huge step changes. "About to bite us" is definitely hyperbole.