Excellent point, Alex, about the economy and people spending like the money will always just be there. I wonder if that's part of the "business as usual" days of Noah thing, as I think you alluded to. A complete economic collapse would certainly be a "sudden destruction!" Think about how we follow the stock market. When something good happens, the market goes up, and when something bad happens, the market goes down. Now imagine that God calls time on the Church Age and pulls us out suddenly. In addition to the human confusion and destruction of cars/trucks/planes crashing when their drivers/pilots disappear, this sudden Rapture of the Church will probably also cause a bottoming out of the stock market like no other. The already-weakened euro and dollar will collapse completely, and those left behind will be frantically looking for someone to calm them and reassure them. There could be runs on banks and grocery stores and retail stores like Wal-Mart as people suddenly realize they'd better get stocked up for survival purposes. This could lead to riots, looting, and lawlessness like never seen before. At the very least, it would cause the Black Friday scenes to pale in comparison.
One caveat: I am not an economic expert, so if someone can correct me, please do. This is just one scenario that is possible. However, when the first post-Rapture domino is tipped in the Rapture's immediate wake, the rest will follow in rapid succession.
"Oir is leatsa an rioghachd, agus an cumhachd, agus a gloir, gu siorraidh, Amen." ("For Thine is the kingdom, and the power, and the glory, forever, Amen" -- Scots Gaelic)