It seems we're drifting away from the main subject.
Count me in!

>> Of course, my own way of eliminating GMail problems is: Don't use
>> GMail, and you thereby magically avoid GMail problems. ;->

It's 2020. Snowden leaks started in 2013.
.
(Also, it seems to be stylized as Gmail, not GMail)

>>> It's increasingly hard to exchange e-mail between lesser known providers
>>> or even self-hosted servers and GMail accounts.

?
If your emails are being refused by others, including major email
hosters, I would kindly suggest you check you got at least correct SPF +
DKIM entries. You can throw DMARC into the mix if you wish so, too.

>> This does _not_ accord with my experience. In my experience, if you run
>> a spam-clean and RFC-compliant SMTP operation and take modest
>> anti-forgery measures (such as my domains' strongly asserted SPF RR),
>> your mail domain will have no problem bidirectionally communicating with
>> GMail / Googlemail -- without spamboxing or teergrubing, etc.
>>
>> I keep monitoring this situation, and it may change, but that is still
>> my honest assessment from many decades of self-hosted SMTP smarthost
>> operation.

Yup. Own mail server here.

The last problem I had was my server refused an email from some classic
corporate suit-bearer (their line of work being IT)... because it was
too big.
Yup, Postfix's default envelope size limit is 10240000 bytes (which is
neither SI - 10.24 MB - or IEC - 9.77 MiB).
You read correctly: someone tried to send me a >10 MiB email, mixing up
email with a decent out-of-band file-transfer technology.
(For the full story, the attachement was some popular slide-producing
proprietary format. Had to accept 30+ MiB for that crap to arrive in my
mailbox. Switched the parameter back to the default value right
afterwards and never ran into such a problem anymore, with anyone.).

> I'd like to echo Rick's observation: Running a mail server is
> still totally doable. I say still, because the viability depends
> on there being a nontrivial pool of mailbox owner operated
> mail hosts. And it is bigger than mail - a good and free
> internet depends on reachable, static IPs with proper DNS
> names being held by the general population. So it is truly
> worth it to spend a few dollars a month to get a VPS/VM/staticVPN and do
> something with it. Like muscle and brain-cells, those things
> can disappear if you don't use them.

Self-hosting, self-hosting, self-hosting (am I mimicking someone crazy
shouting "deveopers" on stage?).
Seriously: self-hosting. Oh, and cipher + forward-secrecy + out-of-band
channels whenever required.

It's saddening to assess how little is known by the general public
(including people who actually work on technical matters in IT) about
key technologies, like DNS (the mother/father of all) or email.
One of my crusades for years: Yes, '+' is a valid email address
character, please stop copy-pasting the same regular expression which
denies it. A tiny glimpse on how inadequate mail-related Web forms
usually are.

Internet should not rely on a pool of self-hosted services. It shall
become the Internet again, as in inter-net, inter-network, ie a myriad
of hosts which are just that: hosts. Everyone hosting... his/her own
services.
Some technology has been there for 40 years now, and it's still deemed
'too complex' by people who actually don't care (but will never admit it
with those words). Cue consumerism.

> Regarding mail: I have this hope that a personal
> mail server will become proper status symbol, and maybe
> even a heirloom. Rick will remember a mailing list called
> linux-elitists@ which didn't allow certain User-agents to
> subscribe. It would be nifty if there were a mailing list,
> with another pretentious title - say inet-lords@ or net-kings@
> which only allowed posting from addresses starting
> with admin@ or, even better, abuse@ as these addresses
> are reserved and unlikely to be given out by providers...

IIRC, some FreeBSD (NetBSD?) IRC channels do that with IRC clients.
Apart from the fun of technically doing it, it might be seen as having
fun at the expense of others, showing self-righteousness & definitely
throwing off those who are different. Not very inclusive not showing
social qualities like empathy. And definitely polluting the signal of
technology serving (human) lives, not reverse.
This kind of jokes works inside an air-tight group.

Bernard (Beer) Rosset
https://rosset.net/