The points you give under 3,4 and 5 are pretty much the cause of the declining American nation.
For farming, we need a total overall of policy. Not only are farmers going out of business because they can't sell at a high enough price, but at the same time the government is subsidizing some farmers hugely, keeping the supply far greater then the demand.
One thing the government needs to do is take a huge chunk of the marginal land, buy it up and convert it back into wilderness. Another thing is to take the rules on pesticides, fertilizers and other such and tighten the rules way up. Both of these things would help both the ecology and the economy. Yet another good idea would be legalizing hemp, hemp is a very durable plant, going well in areas that won't grow food crops effectively, and has many manufacturing uses.
Manufacturing policy is more complex, but a lot of it could be covered simply by not giving MFN status to countries that abuse their labor force to produce goods cheaply. Disasters like NAFTA are exactly why there is a growing anti-globalization movement. It's not the anti-UN ranting of the American right wing, but rather an anti-corporate movement that wants to keep companies from destroying the environment and abusing people.
The stock market problem has been recognized for a long time. I've heard of economists that suggested various solutions since the 80's. The best idea I've heard is to impose a tax on transactions that goes down with the length of time the stock is held. This would force people to invest in companies with an eye to the long term growth of the company not's it's next quarters growth. Something similar would have to be imposed on various indirect options to keep them in line with regular stock purchases.
The other thing we need to do with the stock market is somehow dislodge the idea from people heads that the stock market tracks the health of the American economy. There are many situations where the stock market may be going down but Americans in general are better off.
I gotta go, but I'll get back to point 5 later. It deserves it's own long rant anyway.
Jay