The impact of the New Deal on post-war prosperity is debatable, but I want to focus on two different points. First, the New Deal mobilization is small in comparison to what has been proposed in the context of the "Green New Deal." From 1930 to 1940, total government spending (at all levels), jumped from 12% to 18%. That's 6% of GDP, or about $1.17 trillion annually. It's unclear what folks who use the phrase "total war mobilization" mean. If you're talking about the Green New Deal's proposal of hitting 0 carbon emissions within a decade, that's not close to enough:
https://www.factcheck.org/2019/03/how-much-will-the-green-ne...> Pollin, however, strongly disagrees with the resolution’s aim of getting to net zero with just a decade of investment. “I think it’s completely unrealistic and it’s not worth costing out,” he said of the Green New Deal.
$1 trillion is the price tag of a much more conservative approach that puts a much longer timeline on carbon reduction:
> Edward Barbier, an economist at Colorado State University, agrees that a strict timeline isn’t realistic. He advocates jump-starting the transition by investing about 5 percent of GDP over five or so years. GDP was $20.5 trillion in 2018, according to the Bureau of Economic Analysis, so that’s a little over $1 trillion a year. “That would push us on a path to clean energy, and a path that permanently lowers carbon emissions,” he told us.
The second point I want to make is that we have much less headroom to do a "New Deal"-style project than we did in 1930. We are actually already far in excess of New Deal-era government involvement in the economy. (See my link above.) Today, government spending is at around 35% of GDP. We are in fact closer to the "total war mobilization" of World War II (where spending peaked at 45%) than to the New Deal era 18%.