I don't suspect this will happen until sometime late 2015 at the earliest. There are many factors involved and not enough inertia to move organizations.
1. Transactions for product from merchants using bitcoin is currently weak especially in the U.S. their primary territory.
2. As noted earlier the tax questions remain.
3. The marketplace needs to decide if bitcoin is going to be a currency or an asset security. Those investing for the hopes of an increase in the price of a bitcoin are not going to spend it on a latte at their favorite merchant or a music album download from amazon. "I spent the equivalent of $5US in bitcoin on a latte...if I saved it it would have been worth 10x that"
. This is a big challenge for marketplace as a whole. If using it as a currency does not increase many would say that this is nothing but a ponzi scheme. Could it be both? Yes but the currency side needs to have more activity and not just in micro locations.
4. The state of Ohio recently banned it for use for the sale of alcohol since it is not a "currency". This is not helping.
5. Recently Gyft announced you could buy Walmart Gift cards with bitcoin and then just as quickly the offering was withdrawn. This is a red flag for many of the larger retailers.