Though I agree with the points in isolation, this entire defeatist attitude is what created this problem in the first place. Within the last year I starting running my own email server with no previous experience or knowledge on the matter. I have learnt an incredible amount about the technology and unfortunately the disadvantages that come with it along with the monopolies by big corporations that have defacto control over the email infrastructure on the internet.
It is ironic that I have at times had my email server blocked for no reason by say Microsoft/Google but my sever has never sent a single spam in its entire history of its short existance; which itself is part of the problem (it has very low reputation); and yet 90% of email spam on the internet and especially what I have always recieved comes from email addresses hosted from those two big email providers; yet they never dare block each other.
I am annoyed by the actions of the earlier self-hosted email server administrators that in the past never made a decent and sustained effort to challenge these big corporations in the email space and help protect it from monopolisation. If they had made the effort that people such as Louis Rossman and others are making for sake of Right to Repair we wouldn't be in a situation where self-hosting your own email server is such a pain in the arse because large corporations can block internet transfer of emails at a whim for no other reason because they feel like it.