along these lines, note how many news stories etc are currently touting the power of stock indices and index investing. given a shiller pe of ~28, i'd say most are in for a very rude awakening (again and forever).
A good recent discussion of this: http://brooklyninvestor.blogspot.com/2016/11/bonds-down-stoc...
http://qvmgroup.com/invest/2013/06/22/sp-500-pes-versus-10-y...
As long as people don't panic sell in the next crash, they should be able to ride it out and break even in a decade or two. Unless we end up like Japan, that is.