You are so naive. I suggest reading about the role Madison had in writing the Constitution
I know full well Madison's role. I also don't give a crap. He's long dead. His words aren't some kind of inerrant biblical scripture. Its his opinion that the government of the early 1800s shouldn't do public works; fine, he can believe that all he wants. The government of the early 2000s does public works, and should. There's been 200 years of jurisprudence, plus a huge change towards federalism as a result of a civil freaking war over the issue, and the Constitution has changed both by amendments and by accepted interpretation. All along it was for promoting the common good, and that part IS in the Constitution, but the country is allowed to change its mind about how precisely that works.
We also don't have slavery anymore, just FYI, but Madison was all for the 3/5 clause, so maybe we should bring that back to please our demi-god ~*Founding Fathers*~?
I really can't think of one instance where government policy has helped the economy...ever! Lack thereof..yes.
Regulations..no.
Then go read about the cyclical bank panics and crashes that were disastrous to the economy for decades before the Federal Reserve and FDIC put a stop to it. The government has done tremendous good for the economy by putting in regulations that have smoothed out the booms and busts of the past - not perfectly by any means, but it's way better than it used to be. Also the highway system, airports, police and rule of law enforcement, investment in science and technology (for example, the internet we're using for our dumb forum), etc., all crucial to a functioning economy.
Not to mention made the economy incredibly more humane and in service of the people involved in by things like clean food and water, medicines that work, schools for children instead of laboring in mines and losing fingers in mills, etc., etc.