Also, I see way more junk mail in my mail box than I do in my email inbox ...

What about in your spam folder? You sure it isn't just a case of good Bayesian filtering?

Cool business idea: Bayesian filtering for snail mail.

From what I understand, all spam in mailboxes appear from cooperation of USPS with advertisers, since most ads do not have any address stamped on it. So it looks like USPS actually distribute spam.

And a paper archive was never lost in a fire or flood.

On the other hand, my email provider has never decided to just throw away my mail because it was too lazy to work its entire shift.

Which absolutely does not characterize the majority of postal workers, but it's happened enough to make the news.

There's no structural reason for any email employee to cause my email to not be delivered, but there is that structural possibility for a demotivated postal worker.

Or something from Ted Kaczynski?