Nobody or 'everybody' is probably thinking 1929 can't happen again because we're so Uber fail-safed these days. The reality is that there is a debt crisis that has been growing and now it's like a bomb about to explode! The long drop could well be sharper than your yellow path in yellow. This metaphorical debt bomb is likely to be more powerful than in 1929, for the simple reason that the whole world is now linked up so 'electronically'. So things like flash crashes are still probable though the financial gurus out there say that there are methods to halt it. I don't believe in gurus.
I'm short in good equity positions that are much better than no-loss, and with ridiculous limit orders just in case a flash crash happens. I'm trailing anyway, so the limit orders are 'just in case'.
The way I would plan to profit from a market crash would be by making a spread bet on the VIX volatility index, which many trading platforms have recently allowed. The value of the VIX is quoted in percentage points based on expected volatility in the next year, derived from the price of S&P options. So if you were able buy the Vix at about 8 during a stable uptrend, you could sit on it and wait as long as it takes for your "flash crash" where the vix could reach 80, giving you a 1000% profit, and the vix will never go below 0. Maybe look into these alternatives to shorting equities as you may be forced out of your positions if they hit your stop loss.
Thanks for the kind words!
There's a nice bull run on at the moment between 16:30 and 18:30PM UK time. I find this better than watching Netflix! LOL. The bull run is conspicuously led by Tech stocks. Recent falls in some of the FAANGS have got greed going. We shall have to wait and see as Mr Trump often says. :)
I'm currently long tech stocks, I believe they will lead the rally and lead the crash. Good luck :)