One valuable lesson here is that being correct but too early is the same thing as being wrong. Webvan vastly overestimated the speed of change. 20 years later and I still get most of my groceries from the corner store. I have friends who do mostly delivery, but that's still far from a perfect experience.
Another is that any startup should ask questions like: what do we think we'll learn, and can we learn that for less money? They spent $800 million finding out the answers to things like, How much do people want to buy groceries on line? and What are sustainable economics for grocery delivery?
They could have gotten the answers they did for less than 1% of what they spent. Build a web site, rent a few trucks, buy most of your groceries from the nearest grocery store, launch a limited test in your most favorable zip code. They would quickly have learned how viable it was, and the other $792 million could have gone to startups with more of a chance of delivering sustained customer value.