This may be true, but also it's one of the most dangerous times to invest in S&P 500: there hasn't been a recession for more than 10 years, which is pretty uniq

This may be true, but also it's one of the most dangerous times to invest in S&P 500: there hasn't been a recession for more than 10 years, which is pretty unique. Of course this is not a problem if somebody really takes a 50 year view.