There are enough people in Europe, I don’t know why everybody is so concerned. Most people are doing bullshit jobs too, so those people could be doing something more productive, if that is something you’re worried about.
One of the problems that worries people is that people live longer and longer and if fewer children are born the average age of the population will increase. That means that there will be more and more old people that don’t work and likely require extra care therefore reducing the amount of normal workers even more.
Will society survive? Yes, obviously but it could probably have so severe consequences for people, and the countries.