Several years back a Christian minister told me this. Many who join that sect believe that Christ will help them, solve all their problems and give them a happier and prosperous life here on earth. Unfortunately many get in for a rude awakening because things just do not work that way in many cases. We see Christians suffering here on earth from poverty, health problems, family tragedies to persecution and some as we know have died very unpleasant deaths in His name.On the other hand there are many who mock and scoff at Christianity from Ted Turner to Hugh Hefner and they are living that life of Riley and laughing all the way to the bank.
Anyway after several years of not reaping earthly rewards some of these people get very disillusioned with their plights and leave. He said it is practically impossible to get them back after that. Many forget that we are saving our pennies so to speak for our next life and not for this material plain.