For example, if the IRS wants something for you they will never call you first. Heck, they defneitly won't send you an email first. Instead, they send you a letter.
If you are in the process of identity theft, you will want to keep a close eye on your mail to verify there aren't any letters about an account you just opened.
However, wouldn't important letters (like urgent communication from the IRS or similar government agency) that could have consequences if unread be sent as registered letters (where at least in the UK and France the mailman personally hands it to you and asks for a signature)?
It's a legal CYA matter probably, more than a government-collusion thing- registered mail comes with a tight chain of custody ending in a signature confirmation, so you couldn't claim "I never got the notice" when they started to ask for a judgement.
I've not tried to eliminate paper stuff from the electrial company, neither the yearly report from the landlord. But I spend maybe 10 minutes combined per week reading mail, including spam I throw out. I'm confused now :P