[trjordan]

Sort of. If the brand is good (e.g. Amazon), people will come back later to buy.

On the other hand, you can model some buying as periodic, not need-based. I go to the grocery store when I need food, but I go to J Crew once every six months. If I'm traveling this June, I'll delay my trip until July, so while the revenue isn't "lost", it's pushed into the future. My next trip is then in January, not December, and at this point, J Crew has lost one month of my sales forever.

There's a similar effect for many items at Amazon. I only spend so much time shopping, so if I can't do it now, there's some opportunity they miss out on in the future. The aggregate ends up looking like revenue that's lost forever.