Accountants can’t destroy wealth. There is more stuff now than last year and stuff is what wealth is. The amount someone is willing to pay for my stock has changed, but the stuff that is the company has not. Was the stock ever ‘worth’ $40? Is it really worth $12 now? I don’t know, but I still like the company and still own a lot of stock. We got a PS3 and a 50” plasma this year — THAT is wealth ;-)
The concept of wealth is highly psychological. If you have something (like a house) that people will pay a premium for, you have wealth. If they won’t pay what you think its worth, you’ve lost wealth. You can argue if its a real loss or not (as you still have the house), but perception is often reality.