Whoah there, that's rather overdramatic. First off, most developed countries offer cash incentives for women to have babies in the form of child benefit packages. These incentives are not aimed at increasing birthrates but child welfare. Increased brithrates are an unintented consequence.
Second, although birth-rates have been declining, immigration will keep populations growing for the next decades. In the long run, population growth will be stopped and reversed in most European countries given current trajectories, but when and to what extend is not is as clear cut as you may think. Mostly, the decline in birthrates in fact seems to be bottoming out. Moreover, many would argue that lower birthrates are a positive byproduct of modernization for a number of reasons. That, however is a normative debate.
Now, I do not understand at all why you would say something like 'waaaay below number to sustain culture'. What do you mean with 'sustain culture'? The only problem I see is the sutainability of certain welfare state provisions in the context of a changing demographic age structure. However, that demographic structure is changing because of a spike in birthrates known as the babyboom and increased lifespans due to technological advances. Increasing birthrates is not a solution but merely enlarges the problem and moves it further along in time.