I just gave you a specific example that shows how your assumption is not always the case and you didn't resond to that at all.
So, under your premise, exactly HOW is the income a farmer receives from selling his crop easily hidden?
On this one, I agree with Comrade to some extent.
1) All personal wealth does not generate income all the time.
Corollary: some personal wealth not only fails to generate income, but its valuation can decline. A farm can lose value, for example.
That's risk, and it's part of our system even when the results are sad and out of control, as with farmers in Wisconsin this year.
The more diversified someone's wealth is, the less chance he'll be wiped out due to losses in one sector. A farmer who had other assets and investments would be on firmer ground than one who only owned a piece of land and a tractor. That's part of how richer people keep getting richer: they're less vulnerable to being wiped out by one catastrophe and for that reason are able to take greater risks.
2) Even the income (in a good year) from farming could be hidden. An example would be growing marijuana. Other examples might be bookkeeping tricks that hide part of the income from a cash crop such as vegetables sold at a roadside stand or farmers' market.
The deal with the tax code is it has to be written to cover a wide variety of real-world situations, foreseeable and not, favorable and unfavorable. And given human nature, people will try to find ways to bend the regulations or get creative with their application.
All of which doesn't change the reality that those with great wealth are in a position to help support the country that made it all possible for them, as some of them are well aware.