Businesses can't afford to take that risk. It's a shame many of them are put off by the fluctuations but don't realize they can use companies like bitpay etc just to straight get the cash. I guess most just don't see the point in accepting it at the moment.
What about those companies, who decided to keep a part of their revenue in the form of Bitcoins? Both Overstock and TigerDirect had announced (a year ago), that they will keep 10% of all their Bitcoin revenue in the form of BTC. These companies, for sure must have incurred heavy losses, as the exchange rates slid from $600 to $240.