The foolish are once again getting giddy with the markets. The current market growth is as artificial as previous bubbles. A few people in the know are fanning the flames and enticing the suckers to risk their money, and they will bail out just before the next crash. Insanity is doing the same thing over and over and expecting different results.
I'm not sure how foolish they are. Inflation will make the value of cash drop and the same for bonds. Stocks are comparatively immune to inflation, in the sense that you still own the same fraction of that company regardless of the value of the dollars used to price that stock. It's artificial, but they might weather inflation better than those with other investments (other than brass, lead, and blue steel, of course).