Did George W. know ANY of these men? What exactly does the Treasury Secretary do? Monetary policy is set by the Fed and, other than having some influence on the dollar, Treasury pretty much goes along with administration policy on taxes and spending.
He probably didn't know them. I'm guessing he went with the advice of misguided political tacticians. How the the public perceives them is another point.
As you say, the Treasury Secretary runs with the administration's economic program. But he is one of the key spokesmen. He is maybe the most important team leader for projecting the message to the public. A Wall St insider type, as has been proved several times in a row now, is not the right choice if the President is serious about economic reform.
Robert Rubin is viewed as a genius for having steered "Clinton's economy" through his second term, and there was no bigger Wall St. insider than Rubin.