This
>>939209Not this
>>939160OP, the answer to your Q is extremely complex. But I would say in a nutshell two things.
1. Much wealth is destroyed. This happens for several reasons, including that assets formerly being productive are no longer producing: a factory running at capacity in good times is worth much more than the factory a year later when running on skeleton crew.
And a lot of the money in our world is not "base" money, as in actual dollar bills, but rather money created by the financial sector. Here's why: Assume you make something and sell it for a dollar. You put that dollar in the bank. The bank does not keep that dollar around, it lends out $0.50 to $1.00 of that (depending on regulations) and keep a fraction in reserve. The person they lend it to can put it in THEIR bank (or their purchaser's bank) which does the same thing. Thus your $1 of money can lubricate $5 of transactions in the real world. When the markets crash, the fractional reserve system contracts and the total amount of money shrinks. That's bad.
2. Some people will inevitably profit from the crash. The big banks, for example, placed large financial bets on the collapse of subprime mortgages while telling their customers to buy. Those assholes profit. But the profit is not equivalent to the net economic loss for the reasons spelled out in 1.