I support the author but let me tell you a counterargument I don’t think he devotes enough to:
Spam is a real issue.
The amount of spam emails which get sent are absurd and likely orders of magnitude more than non-spam. And spammers do a lot to mimic real emails, including just hacking legitimate addresses and adding them to botnets.
Even on gmail, I still get spam sent to my inbox. Fortunately very rarely, but it still happens.
And even if it isn’t bad today, spam has the potential to be much worse in the future with transformer networks and hostile state actors.
And even if it really isn’t that bad and never will be, the big companies and those arguing against self-hosting will claim it is. They don’t want to allow a relative few self-hosted email servers in exchange for much more difficult and less effective spam detection. Forget Gmail and Outlook, why not just use Fastmail or Protonmail?
If you want a legitimate argument for self-hosted emails you need to address the spam. It may be as simple as registering your official email with some organization sponsored by open-source, and all the big companies can trust that one organization. Then the org has to deal with spam registrations but maybe there won’t be much and it will work out. idk much about self-hosting so this org might already exist.
But this article doesn’t mention that org, in fact doesn’t say much at all about spam besides “keep existing spam-prevention because it already works”. But you should at least explain why. Because spam is a legitimate argument for big-co forming an oligarchy that’s not just “so they can make more money”, and it’s the main argument that big-co uses.