My votes, albeit simplistic ones:
1) Pastors are into numbers. Church growth = success.
2) Believers are too caught up in materialism to take the time to be believers. Tyranny of the urgent and all that. "What would Jesus do" is a slogan to wear on a child's trinket. Don't have time to read Shelton's book much less the Bible, but hey, don't mess with my Sunday or Monday night football or West Wing, Desperate Housewives, Apprentice, Extreme Home Makeover, CSI, or American Idol!