This is why the U.S. government did not spend millions of dollars on the development of internal-combustion gasoline engines in the year 1815.
This is why the space program goal of landing on the moon before 1970 was not financially wise.
Ambitious government technological goals during peacetime are great for politicians but never financially worthwhile.
The only successes that are had is because the actual work was performed by private-sector companies. And in cases where “the fix is in”, like green energy (meaning the private sector company has assurances that wasting the money would be fine as in the case of Solyndra), the private sector simply takes the money they are given by their political crony.
The Hoover Dam is a classic example of a project being completed only because of private sector efforts - in spite of government attempts to mess it up for political reasons.
Actually, the US government wasted billions on corporate subsidies throughout the 1800s (in 2011 dollars). In the 1840s and 1850s, it was steamship lines and telegraphs. In the 1860s to 1880s, it was steel and railroads. A bit later, it was petroleum. Government subsidies led to sloppy and inefficient businesses that would not adopt new technologies, charged high prices, and provided expensive products only affordable by the very rich. In each of these cases, brilliant entrepreneurs who refused to take government subsidies beat the pants off the sluggards who lived off the government teat. But these entrepreneurs have been traditionally excoriated and reviled as "Robber Barons."
For the full story, I highly recommend Burton Folsom's excellent book The Myth of the Robber Barons: A New Look at the Rise of Big Business in America. It strongly bolsters the argument that the government should get out of the way of the private sector and end its wasteful market-distortions.
The tale is told that the dam, originally called Boulder Dam was renamed for Hoover at the cost of several thousands of dollars, for signs, buildings etc. while for about $10 Hoover could have gone to the courthouse and just changed his name to Boulder. Government...in action.
Just a little 'Rest of the Story'.