Because there is a post office in almost every US town with postal mailboxes available? You can use that to have all USPS packages and mail delivered.
There are also UPS Stores, Fedex Kinkos, 7-Elevens, etc. which offer the same service, plus allow from delivery from private carriers.
On top of that, for 99% of Americans, having your package dropped off at your door is just fine. Nobody is going to take it. And if you're that paranoid, just have it delivered to your neighbor or to your office.
I really don't understand what void this product is trying to fill.
You really can't pull numbers out of a hat like that. How many people live in an apartment with no front doorman, or requires a buzz code to get in? Probably more than 1% of Americans.
Or what if you ordered a shiny new laptop from Amazon? Would you leave it at your front door, even if you live in a safe area? I personally wouldn't.
Plus, These guys started in Canada, it's unfair to judge from purely American point of view.
I was hoping to see Drop Locker (pivot of Laundry Locker, as I understand it) get into this in San Francisco, but so far they seem to just be looking for partners without having found any.