Is this actually a bad idea? We won't know until someone tries it, and deals with the issues. The author's attempts at prognostication cloud what is otherwise a well written and perceptive post.
But I would be happy to be proven wrong, and I'd bet some cold hard cash on failure...
Your first point is spot on. It is going to be hard and fuck to figure out the logistics issues with this idea. But not impossible. Does it look like the The People’s Parcel will be the people to do it? Probably not.
This idea already exists to a certain extent. Check out keychainlogistics.com.
As I said, though--definitely happy to be proven wrong. It would be pretty amazing.