The S&P 500 didn't exceed 1929 highs until 1954. Not saying it's a perfect parallel, but there are definitely precedents of stocks not working well for decades.
No, you're not including dividends. It had positive returns way before 1954. But yeah the 30's was called a depression for a reason.
Just to put a date to this: including dividends, it matched its 1929 high again around 1943/1944.
What if you continuously invested over that time?
Recession does not usually mean a stock market crash either
It does matter: it's time to get your "buying kit" prepared because good deals are around the corner.
Yup, trade bonds for stocks. Never go 100% on stocks. As Buffett says: "I will never be caught short on cash".
Sometimes corrections do matter. If you bought at the peak in 2000, including dividends and adjusting for inflation it would have taken 13 years to get back to the initial level. Maybe it’s nothing, maybe the S&P 500 won’t get back to 3000 in a while. Probably it’s nothing...
Hard to say. I think we've entered a period of time when extremes (black swans) are the new normal.