First and foremost, you claim that the founders were "overwhelmingly Christian", I'd really like to know what qualifies as "Christian"? Seems to me that Christians are willing to point out that America is "overwhelming Christian" pointing to polls that indicate that 80-85% (you said 90% a number that I'd dispute), but when specific Christian behavior (the Ted Haggard's of the world) is pointed out, your told that people that act in ways contrary to Christian faith aren't "true" Christians.
My guess is that the "true Christian®" population in the US is 20% or less, with the other 60% or so being moderate Christians or people of other faiths, who look to their religion to provide a sense of community and general moral standards the other 15-20% are non-believers. Many of the moderates don't believe in Noah's Ark, the Garden of Eden or that the earth was literally created in six days and Jesus may or may not have been a real person, in the end it doesn't matter to these folks. Most of them believe that the universe is as old as science says it is and that evolution is the best description on how species have changed and adapted over millions of years.
Christian culture is very pervasive and has the benefit of incumbency. I'm often amused when two "god fearing" Christians find out that the other was only pretending to be Christian and going through the motions, to better fit in with their neighbors and families and out of fear of upsetting their spouses, so as to gain the social benefits.
The fact is that the founders, regardless of their personal beliefs understood that religious freedom (and by extension the freedom not to be religious) was of paramount importance.
We are a secular nation comprised of predominantly Christians, but that fact gives Christians no specials rights or standing in the eyes of our government.
You seem to imply that being Christian should lead to a higher moral standard. Ironically, many of the statistics you cite, Wages, unemployment, prison population, healthcare....These statistics along with others like teenage pregnacy, violent crime, and standard of living are best in countries whose majorities are non-believers (Most of Scandinavia, Japan, and to a lesser degree France, England, Germany....)
In our own nation, all you have to do is look at your statistics and correlate them to the areas of our nation that are the "most Christian".
Mississipi, the poorest, most overweight, with the highest rate of teen pregnancy, lowest life expectancy, just happens to be the "most Christian" state in America.
I don't believe that Christianity is, per-se, to blame for social ills, but I do believe that Christianity is used by unscrupulous people (politicians included) to mislead the poor and uneducated, which statistically are more likely to be devout.
Overall you seem to insinuate that being more Christian is the solution. I think more education, empathy and an understanding that people are one of our most valuable resources in America. Investing in our people will, IMO, have the greatest affect on our society and culture and will result in better measures in virtually all of the statistics you've pointed out.
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