The Earnings Yield (earnings / price) (red line) Peaked Three Years Ago
Subsequently, the rise in the market has been due to Central Banks, HFT, and Etraders locked in their own momentum feedback loop. Even in 2007, the Earnings Yield kept pace with the market:
A Bubble on Top of a Bubble
Stock prices are outrunning profits (above) and profits are out-running GDP (below). The unsustainability of this double bubble, can't be remotely over-stated:
Profits versus GDP:
In this casino the only cashier is the next dunce who walks through the door