If you think your only competition is Wonderbread, then that makes sense. However, there are places like Trader Joe's and Whole Foods that offer bakery fresh high quality bread that isn't "tough to find" - they're everywhere.
It's a markup, but $6 really isn't much considering it's delivered to your door. People have made similar dismissive statements about a lot of the to-your-door service startups, but the market is flourishing.