And you don't have any control over what they blackhole or reject without even delivering to your inbox/spam folder, if you're their user. You don't get to see logs either.

And big benefit of self-hosting is that you can actually make your server receive everything with no rejection or blackholing. So in that sense, self-hosting can actually be made extremely reliable for reception, and that is much more important to me than reliable sending. So I'd say self-hosting is superior when it comes to reliability, because at least you can make one direction "100%" reliable. With big freemail you can't make any direction comparably reliable.

As soon as you get some IP address reputation, sending gets fairly reliable too. And it will also work fine without any modern cruft on top. You really don't need spf, dkim, dmarc or any of that, for your personal e-mails to be delivered.

Kinda unfortunate that others sometimes block you when you're starting out just based on your IP address [range], so it's discouraging, but it mostly works after a while.

It's symmetric in the sense that if Alice can't communicate with Bob, then Bob can't communicate with Alice. But network effects break the symmetry. If you have a big provider you can reliably communicate with 99.99% of people. If you have a small provider you can reliably communicate with 95% of people.

*Numbers made up to illustrate the point.

So if big provider drops 95% of incomming emails from non-big providers into black void, their service is less than useless to me, and their quality would be at par with small providers that can deliver 95% emails successfully.