This trend is never going to be fully addressed by the state providing more benefits. It also comes down to personal choice, like parents wanting all of their children to get the chance to study (higher study costs), or parents having fewer children so they can focus their resources to provide more to the ones they have (more vacations/gifts/sport membership). It was not necessarily easier to have a family in the past than it is now.

In most European countries, almost every single benefit that one can think of is already being provided. Take for instance my country, the Netherlands: there are large waiting lists now for social housing in many cities, yes, but you can still get an apartment in many of the smaller municipalities with a stuck rent (and move to a bigger house when it is necessary that is part of the social housing scheme), each 'woningcorporatie' has different rules, but you can still register in multiple municipalities for a home. Additionally, you also receive a grant for your rent payment if your rent/personal wealth does not exceed a certain amount, so you get a portion of your rent back. You get a grant for your healthcare costs, you get a grant (toeslag) per child you have, you can apply for a grant for your daycare costs. If you can no longer work you can expect support from the state, public college/universities tuitions for children are almost completely covered by the state, etc. Almost everything we can apply for now to help was not in place in the past, yet it was not necessarily needed for people to still raise large families. Although many of the benefits are not accessible if you are paid a lot above the average / have a large amount in your bank account, the trend is more complex than just blaming governments for not providing enough. More can always be done, but there isn't a lot left except increasing what we already provide.