It's my understanding that big events like the Great Depression and Great Recession happen because humans are very good at being stupid, but lessons are often learned via policy and law. I'm no financial historian, but it's been my understanding that new laws have been put in place each time to prevent these things from happening again. Was the Great Recession as bad as the Great Depression? No. Hell, no. Many of the issues that caused the Great Depression were mitigated by new policies. Will the next recession be as bad as the Great Recession? Probably not, since other policies were enacted to curtail the dumb things that created it. Chances are that yes, humans will find some other loophole and think they're geniuses again and get burned, but even if humans have a short memory they often make up for this by enacting laws. I'm not a big-government guy, but I'm not convinced I'll see another Great Recession in my lifetime. Recessions? Yes. The Great Recession? No.
Sure, maybe things ARE a bit overvalued right now. These things get fixed during corrections, but money keeps flowing. If stocks are sometimes overvalued by people, then they are sometimes undervalued at as well, so even if the stock market loses something crazy like 50%, it will likely rise up soon after. What was the statistic, again? That the market had essentially recovered a year and a half after the Great Recession? The consequences lasted longer in the form of unemployment, but still. I don't fear corrections in the market: those should be expected, and they are accounted for in the 4% rule.
