It may drop to 6000, or even 5000, but it simply can't drop to zero because that would imply that there were no assets or productive capacity backing the stocks, and that is simply not the case. At the very core of it all, people need food, water and energy to live, so the assets that produce those things must have value.
The market will eventually reach a level where all the "fake" money, that is bad debt secured by nothing, will be purged, and that is the true value of the market. It will then rebuild itself from this "true value" base.
What you will see is discretionary consumption taking a big hit - in other words, people will stop buy things they don't need like TVs, meals out, travel, new cars, etc. They will hunker down and do their best to pay their mortgages, feed themselves and simply survive. Unemployment will rise significantly, and with it homelessness and crime.
The world is in for a tough ride, but it will eventually recover. The sad thing is that the ultra-rich ers who caused the meltdown by scamming each other and the public will mostly be insulated from the fallout, while Joe Average who works at the Hilton will lose his job.