@flyaway, I just want to point out that if you removed the words laissez faire and replaced it with “communism” you’d get exactly the same argument that hard-core leftists make with regard to Marxism. Those folks often say, “well, pure Communism was never tried. If Stalinism hadn’t gotten in the way…”
Witness:
“No, there is no proof that it doesn’t work; just because there is no proof that it will work does not mean that it won’t. And it was a hugely popular idea that influenced our economy in many ways. [Karl Marx] was not the only man to support [Communism], he was merely the first one to publish a book on it.”
I think it should give you some pause that your arguments precisely mirror those of extremists on the other side of your issue. Perhaps, instead of insisting that “the theory makes sense” so why don’t we try it you should consider that the actual economic systems that currently exist are far more complicated than those under which any “pure” economic theory would work (that includes both “laissez faire and communism.”
Post Script: Have you actually read “Wealth of Nations?” (this question is not intended to be disrespectful in any way; I’m actually just interested)