If we're heading into a demographics crunch NOW, we'd be best to reign in spending as much as possible now, with the expectation that things will get worse in the future. If we spend now, we'll be increasing the debt even more, which will make it harder to deal with the debt in the future.
I disagree - we need to prepare things like the health and support systems for the coming crunch (over the next ~20 years) and we need to do that now. At the same time, we have to do things like improve our infrastructure and productivity to make up a gap in the total labour pool.