Well, not everybody, but some of us we do. Let me explain myself:
12 years ago after reading about TipJoy, a Y Combinator startup, I thought that this might be a scheme that could be used to force mass senders to pay something in order to ensure (via the investment cost to post to my inbox). I just thought of it kind the wrong way, and not in terms of snail-mail. I thought the recipient should be paid to read the email. But anyway TipJoy folded and life did its own thing and this was an idea left to collect dust.
It turns out that a whole industry focused on email delivery sprang in the meantime. IP reputation became a thing and the small server you operated from your house was part of a dialup or DSL pool that was used by spambots. No matter your intentions and your rigor in setting up your email server, your sender’s reputation was next to nothing. The same held true for your ISPs outgoing mail server too. The same is (still) true if you try to setup a VM to a cloud provider (if you’re allowed to send outgoing email at all). Once you needed to know about SMTP and POP3 only (IMAP too if you wanted to be fancier). Now you needed to learn new stuff too, SPF, DKIM, greylisting, RBL, DMARC, the list goes on. That’s how the sending industry was formed, providing guaranteed delivery, metrics like open-rate and more complex analytics.
Here I am now, some years later, and I am running a small mailing list for the Greek Database research community (I am not a database researcher, just a friend of the community). This mailing list always had reachability problems, even when I was running it on infrastructure I totally controlled when I was working on an ISP. Spam bots and inexperienced users always resulted in some sort of blacklisting that a single person postmaster team struggled to handle. There were delivery problems with a lot of personal time devoted to unblock them.
Since 2014 that I quit the postmaster business, I am running the list using Mailgun (It could have been any other M3AAWG member, I just picked them because of Bob Metcalfe mentioning them on twitter sometime). They used to provide a free service and the list was well within those limits, but they changed that. So there’s a monthly cost that varies from $1 to $10 depending the traffic. Delivery has been stellar ever since I switched to Mailgun and the few issues the mailing list had, were glitches from my side.
So it turns out that you do pay some postage to send your email after-all and the M3AAWG members are the couriers.