Demographics are very important and they are very difficult to alter. This article describes the effect of demographics on the eurozone economies. Germany has the strongest economy but demographics are working against them. Other countries in the eurozone have similar problems but they have very resources at their disposal. The demographic problem is well understood but it is not easy to change fertility rates, and it is not easy in many countries to integrate immigrants into their economies.
We have seen how Japan's economy has been slowed down by demographics and how some countries are benefiting from favorable demographics. Slow growth is not necessarily bad but countries that have seen rapid growth, partially the result of favorable demographics, will have a tough time dealing with the political fall out from slow growth. Expectations of rapid growth have been determined by the experience of rapid growth.