The economy is a collection of segmented markets. Some 'segments' within this collection may collapse, but will always build themselves back up again. The economy is a self cleansing and self healing mechanism.

Barring certain currencies, there has never been an instance in human history of a financial market that has crashed and then disappeared entirely. The tech market plunged in the early 2000's but rebounded... Between 1930 and 1970, gold lost a TREMENDOUS amount of value... but that market has also recovered.

The "world economy" is never going to "collapse" simply because there isn't a world economy... Just a collection of segmented markets that are designed to go through cycles