This link is to 2014, specifying that stocks are overvalued and set to underperform. Imagine if you had taken your investing advice from this source. It would have been life changing results, possibly moving from having financial independence or a secure retirement (as you may now have) vs. having invested in “value” stocks or commodities, T-bills whatever.
“Overvalued” is both a subject and objective term. But when a stock is called overvalued, but is based upon backward looking metrics, or by not looking at forward looking CAP and SAM but just reverting to the mean, that is where the best performing stocks in the world come from.
By all means, let us never again invest in an “over valued” market that is not in a bubble.