I think before long there will have to be some sort of incentive in most of Europe for people to have children.
Pay fair wages in secure jobs. Make property affordable.
Since the powers that be have no interest in that, and indeed they're actively incentivised to reduce wages, decrease security and make a roof less affordable, then the decline is inevitable.
They'll eventually pay a massive price for that, and they're starting to now with all the political upheaval, but the people who are doing it now will be dead or counting their money by then so they won't care.
I do appreciate how this went from a mostly not too interesting thread to an interesting conversation about a slightly different topic. Being from the UK I can't comment as precisely about the situation in other countries but I imagine it is not too different. I've seen such alarming statistics about the rise in house prices and their affordability. But within the mainstream media and the political spectrum there is little sympathy for young people, people are stuck in their own era and are too quick to point to laziness instead of realising that times have changed and the younger generations of today work equally as hard, they're just not afforded the same situations.
From a biological point of view the long term effects could be damning, or potentially beneficial in some ways (although I don't agree with that). If you assume only the most skilled and capable people are able to earn enough to support themselves and a family then the global gene pool should strength. Of course that is if you think everyone has a level playing field which is in my opinion far from the truth.
The main difficulty with population control is that governments tend to act in a reactionary capacity instead of being pro-active. But it doesn't take a genius to see that something such as population isn't going to change over night, it takes time for the full effects to be seen.