I find the concept of church or a god in the classic PS series interesting.
Perhaps I look for existentialist themes in this series, but, eh.
There's no way around spoilers in this.
in the, technologically advanced world of PS1, there are churches. there is even mention of Lasheic coming under influence of 'dark priests' before he becomes a tyrant. and even after his tyranny, he doesnt extinguish the church, which seems the logical step of any oppressive (or logical) regime. Even on Dezo, the people there have their faith. Unsure if the japanese version mentions any more or less of any religions. Perhaps more info regarding Noah/Lutz or Damor the Soothsayer's beliefs?
in PS2, the technologically advanced world of Mother Brain seems void of all churches in fact, one could say mother brain has "replaced" god. even on Dezo, you dont see much of the spirituality the people are known for. The only exception is Lutz and the espers, who cites the "Oh, God of Algo" when healing your party. It makes sense that MB extinguished religion, given the materialistic society and its dependence on her system for fulfillment. The earthmen are morally bankrupt, but its a chicken vs egg argument of which was first, their corruption or DFs influence on their corruption. Scientists of Palm and Mota are pretty bankrupt morally too, going as far as to create genetically modified creatures as Neifirst and biomonsters, which if not seen as attempts to "play god," are at least unethical procedures.
PS3, which takes place 1000 to 2000 years after PS2 depending on your take, has regressed technologically, but they regained the church. At least I assume they are churches by the music and the way the "priestly" men who revive your party look. It does make sense that with thew lost knowledge of technology. different knowledge of mythology arises. Unsure if the "churches" are indeed churches in the Japanese version of the game. But whatever it is, exists. Also of note is the lack of reference to Mother Brain at all. Lastly, it does appear marriages are in "churchy" looking areas in the cut-scenes," with the exception of Rhys at the beginning, attempting to wed in Landen's Castle.
PSIV, has no churches on Mota, and despite a great collapse in society, there is no church to guide people with mythology rather than technology. There is evidence of reemerging technology, but no more than PS3 really. The only church on Mota is Zio's, as misanthropic or nihilistic as it is. Other than that and Zio referring to his "god," the only vague reference on Mota is to dr Lubetz/Luveno,"The God of Learning." Dezo fares a little better. However, there are definitive churches or "temples" for the Dezo people themselves. the Espers, too, seem to be going pretty strong with their spiritual or at least humanistic belief system. They appear to be idol worshippers or at least give that respect similar to ancestor worship, regarding Alis and Lutz. Although this Lutz incarnation isnt too spiritual compared to the Espers he leads. Le Roof of Rykros doesnt use the terms 'good' or 'evil' much, nor ever use terms of any god or devil/satan, but does refer to a "Great Light" and "Profound Darkness." And Le Roof itself is some sort of sentient higher being. And so are the bosses who test you on Rykros. Even that head Bishop on Dezo seemed to be aware of Rykros' role in the good vs evil plight. But as a whole, I'd feel safe to state religion is dead for the majority of algol's population in PSIV.
So, my simple question, is, "What happened?" Forgotten over time? Suppressed by regimes? Suppressed by technology? Logically taken out of the survival equation?