I think Christianity lasts for a long time has its own reason. We wound not discuss whether the reality of religion here, but the model of the church and religion. There are some forces which supports the religion even if the religion cannot be explained clearly.
First, Christians are more "positive" and so they are happier. They think that God has chosen the best path for them. Even if they face failure, they would think that God gives them chance to learn and improve. For failure, they may not care as much as others as they may be more concern about the life after death and religious life. The concept of the life after death also make Christians more "peaceful".
Second, Christians are well-organized. They have clear plan to donate money to church and promote their religion. They have regular gathering and sharing to strengthen their religion. They gain happiness from religion, so they want others to follow their religion. The more important thing is that, according to the Bible, all people go to hell if they don't believe in Jesus. Some Christians try their best to spread the religion.
Last, Christianity is about uncertainty. As human have limit in proving "super-natural" matter, Christians could defense their religion by ignoring any philosophical thinking. As the possibility of life after death exists, Christians could ignore any criticism. Therefore, Christians claims that the religion is "logical correct" as the religion lasts for long time.
The model is of religion is successful. Therefore, many business model adopt similar running method.
For example, insurance company teaches their agents that insurance is helping others with well-organized plan for promotion. People could not deny the use of insurance as uncertainty exist.
Another example is multi-level marketing. The people joining multi-level marketing are told that they could make big money so they are happy about that. The organization is well-organized for sharing "successful story" and recruiting new members. Other people could not deny the possibility of earning big money from multi-level marketing as the probability does exist.