I remember in the 2007 crash, it started on the ASX where a...

I remember in the 2007 crash, it started on the ASX where a large company had used equities as a guarantee with commonwealth bank. They couldn't make their payments so CBA dumped all of their stock on the open market.
So i think when a crash comes, it will be most likely when signs appear of financial stress.
The smaller banks in the US are under pressure, but the FED has shown that they will print their way out of trouble, so the market has no fear if this possible event.
So it has to be a complete system failure like lehman brothers and Enron.
It could be a financial cyber attack or Putin dropping the bomb, but with any of these events it is likely that the markets would be frozen by the authorities.
It might be just a steady slow grind down over a two year period with moments of volatility (eg DMP falling 30%).
We all expected businesses to slow under the weight of rising interest rates, bit i think the cashed up baby boomers are keeping the economy buoyant, while the younger generations grapple with the cost of living. We have wars, inflation, high personal debt, and record realestate prices, and yet the US market just hit a record high! Crazy times.