Well there are logical reasons not just animal spirits, under "normal" conditions some amount of demand lifts market prices a measurable amount because:

1) Workers buy into "it always goes up over a long period" so retirement money gets tossed into the market. However they're likely (temporarily?) unemployed or underemployed.

2) There normally exists a small but lively trading on margins market, day trading market, etc. However the margin / daytraders have been wiped out in the crash and it'll take awhile to grow a new crop of suckers.

3) Stable prices mean stable financial market means stable income for capex means stable growth. Collapsing prices make it hard to raise funds for capex. So you can't make more profit next quarter off a refinery expansion today if you can't raise the dough to do a refinery expansion today due to collapsing prices.

When things stabilize you'll pop back up to normal growth and prices. That might take weeks to decades based on past bubble experiences. DJIA only took from 1929 to sometime in the 50s to break even, inflation adjusted, so it could be 20+ years. Or maybe just a couple months. This being an epic 1929 scale bubble it could very well be 20 years.

I do acknowledge the stereotypical retail investor thing of always selling at bottoms and buying at tops due to animal spirits or whatever, but there are rationalizations beyond the future must be the same as the very short term past.