This is sketchy right now, but I have found that there is a parallel between the rise of church pomp and hierarchy and the threats of hell. My source says that it really hit its stride in the 6th century.
Poor, uninformed congregations may have been repulsed by men wearing embroidered robes and fish-god helmets. They may have resented being ruled over by domineering authority figures, telling them how to act and believe.
The Bible was not available to such people, even if they could read. It was written in Latin, Hebrew, and Greek, and in the past, chained to the pulpit.
Religion as a monopoly was oppressive, even deadly, to those who questioned it. How could it be maintained? By threats, both temporal and eternal. As Stuart Crane said, "There is nothing as frightening as fearing your immortal soul will suffer for eternity. Men who would risk their lives in battle shudder at this threat."
So the greater the pomposity and carnality, the greater the control mechanism needed to sustain it. These are the two rails of the old religions.
Hell is being disproved now, as is the everlasting soul needed to suffer in it. Anyway, it is all so future, and we are a "now" generation.The corporate churches are turning to the "blab it and grab it" approach. They still want your money, not to keep you out of hell, but to insure your prosperity. It's just a new set of rails.