If you had your own primitive civilization, unaware of modern culture, would you experiment religion with them?. To many, this would only be a dream, to have a whole tribe of people, teach them a religion, and see how it spreads, and how their faith grows stronger as the years go by instead of debilitating, to have something like this would be severely detrimental to organized religion as it should be a living breathing example of how people will literaly believe and follow anything an authority figure will tell them via indoctrination.
Some of you will be surprised to know, that this already happened in a way, and sadly, it hasn't had the effect one would hope because not nearly enough people know about it. It wasn't an experiment, it happened by itself on the islands of Vanuatu during the 1930's, the tribesmen began talking about a "John Frum" supposedly an american missionary that spoke how in order for all the missionaries and white people to leave vanuatu, the natives had to reject the modern lifestyle and all of the western commodities.
By 1941 all the followers of John Frum had left the missionary christian churches, got rid of their money and stopped going to school, the authorities then arrested, prosecuted and exiled John Frum, from then on, the belief that John Frum would come back to his followers with cargo was created.
The cult is still active today, one of the leaders is quoted for a response he made to a reporter who asked him "its been 19 years, why are you still waiting for John Frum?" the leader replied "You christians have been waiting 2,000 years for Jesus to return to earth, and you haven’t given up hope.”