Though Nietzsche elsewhere predicts a decline in Christianity, he does not particularly do so here, and in fact one could use this chapter as an explanation as to why it has not declined more rapidly. To be sure, in western Europe it has progressively waned, but even 140 years later it is still plural or even dominant. In eastern Europe, the reign of communism shredded the historical and familial traditions, yet even there a significant population believes. Elsewhere in the world, among educated people, religion has become more fractured and includes practices of eastern religions, some of which are not monotheistic but instead pantheistic, panenthestic, or merely mystical. Nevertheless, some of the same psychological benefits and practices seem to remain.
We might claim that religion today is more strongly driven by values than metaphysics. The greater mobility and general independence from family means that individuals often view their religion as a choice. The Razor's Edge by Somerset Maugham observes a young man who explores his spirituality and finds eastern religion to his liking; at the time (1940s) that was a rare situation, but today it is quite common for young people to do something similar. My impression is that this generally proceeds by first identifying resonant values, then selecting a spiritual tradition that supports those values, and finally accepting whatever metaphysical and other dogmas are associated with the tradition. The most successful religions today are those that match the market for clusters of values, and also support some of the psychological needs outlined here by Nietzsche. Interestingly, those clusters of values seem to correspond reasonably well with those of the creator and of the herd.
Historical analysis aside, Nietzsche's goal here seems to be to persuade the rational, science-respecting individual that he should abandon Christianity or whatever his religion. His approach of elucidating the psychological needs serviced by religion gives the reader pause to consider whether this is "all it is" - especially in that time period, when religion was dominantly held through family tradition. He regularly emphasizes that his scientific, rational viewpoint does not hold the promise, the palliative benefit, the eternal rewards of religion; this represents a bit of reverse psychology to cause the scientific-minded not to want to fall prey to happy falsehoods. Finally, he rounds out his effort with direct argument, such as pointing out the internal contradictions of original sin and the inconsistencies of Christianity with modern science.
For a God-fearing, traditional European audience, this must have been jaw-dropping. As an atheist reading it today, it seems rather obvious, yet it nevertheless helps to explain some of the continuing power of religion and faith in the world.