I hate to break it to you all, but unfortunately, rampant speculation, the hack attacks and massive price drops have already essentially killed bitcoin from the credibility point of view. No large company will willingly use a currency if using it risks their profitability on the scale bitcoin does.
Such a volatile market also has the potential for ENORMOUS gains. People have made quite tidy sums of USD from BTC. THat wont go unnoticed by investors if it continues. Rewards require risk.
How can The ENORMOUS gains be captured by businesses that enter the bitcoin economy? If they can't, then how is this sustainable?
THere are a few answers, however what I think youre asking is how do I expect a business to accept BTC as payment when they dont really know what the relative value will be tomorrow?
It's a chicken and egg question. Until a significant number of businesses accept BTC, speculation will of course drive the market. In that time, the value could go up in the extreme way we've seen in the last month. A business could still profit by accepting BTC as payment, speculating that they will increase in value.
No. What you describe is no different from speculation. You are saying that business can speculate too.
Businesses can only earn more in btc than in USD if they:
a) introduce novel online services that can't be offered at similar costs via USD/EUR/etc/ (silkroad/gambling/ and maybe remittance,webcam)
b) are large enough to influence the BTC price significantly by announcing their decision to accept BTC
But b) won't function efficiently because bitcoin currency generation is set up badly,
see here:
http://forum.bitcoin.org/index.php?topic=19130.0