Well...you may well be correct there. Perhaps there is nothing that can be done to lift western birth rates. If this is the case, then the west is destined to be overrun by faster breeding non-western populations. But, as our consolation, we can all be happy that the "McCulture" of the west will eventually spread to the third worlders themselves....at which time they will cease having kids too (probably long after the west has essentially been overrun). At that time, humanity will be condemned to global deflation.
At any rate, depopulation has long been noted to be a symtom of a dying civilization (read Spengler, for instance). I came across a salient quote by Augustus Caesar, who was facing the same problem. He made these comments when addressing this issue at a meeting of the equestrians of Rome (who were sort of like the upper middle class):
"How should I address you? As Romans? You are heading toward the elimination of that name. The truth is that you are on a collision course with our national future. What would be left of mankind if everyone behaved like you? You are murderers, in the sense of not giving life to those who should be your descendants; and traitors, in the sense of leaving your country bereft of heirs. For it is people who make a city, not empty houses or deserted squares. How can we preserve the state if we neither marry nor have children?"
A good question. One that we will all have occasion to ask frequently in the not-so-distant future.