All you have to do is look around and see how much stuff people have. People have enormous amounts of stuff compared to even 20 or 30 years ago. Bigger houses. More cars. TVs. Computers. Smart Phones. And it's all, relatively speaking, dirt cheap. It's so cheap that storage units are a booming business because people don't have room to store all their stuff in their homes. It's so cheap that burglaries aren't even a thing anymore really because stuff is so cheap it isn't even worth stealing. It's so cheap that Marie Kondo has a best selling book about the challenges of getting rid of your stuff because you simply have too much of it.

Healthcare is expensive. Education is expensive. Land (in some places) is expensive. But man stuff. Stuff is cheap.

Between 1960 and 2007, the share of disposable personal income spent on total food by Americans, on average, fell from 17.5 to 9.6 percent

http://www.ers.usda.gov/data-products/chart-gallery/detail.a...

Correct. While producers of the raw materials (corn, wheat, rice) have seen prices decline when adjusted for inflation, the producers of finished products (Corn Flakes, Wheaties, etc.) have seen prices rise even when adjusted for inflation. But there are only four or five big middlemen, so it's a lot easier for them to capture the increased margins than the tens of thousands of farmers who produce the raw materials.

Similarly, if Apple could reduce its shipping costs to near zero by teleporting the raw materials to Foxconn and then teleporting the finished goods directly to retail outlets, they'd still charge $600 per iPhone, even though they have competition from other phone makers in the form of Android.

The Invisible Hand doesn't always work the way it did in Adam Smith's time.