Bad graph. 
Although the graph’s message is obvious, the time span in it is long: 125 years. Basically, looking at it that way, US stocks have been unpleasantly expensive for almost 10 years now. For those who invested during this period alone, high valuation multiples have not been an obstacle, but an opportunity, as already highly priced companies have risen even further. And yet, in the big picture, it is obvious that price matters and ultra-expensive stocks are not necessarily the best place to buy.