Can unemployed investment bankers build bridges?

Where is Obama going to find 3 million workers to build new ports, medical infrastructure, mass public transit infrastructure and expanded electricity grid and "green" technologies.

We have 1.2 million unemployed construction workers. We have 123,000 unemployed architects and engineers. We have 83,000 unemployed machinery workers. We have 145,000 unemployed transportation-related workers. So that brings us to barely more than 1.5 million of a labor pool the government can tap into for all the new building activity. But the bulk of the joblessness is in financials (up to half a million), retail/wholesale (1.2 million), leisure/hospitality (1.3 million) and health/education (1.2 million). And if investment bankers, shopkeepers, bell captains and medical chart technicians have anything in common it is that they don't have much experience in shovel-ready activities.