I'm arguing that with a system as distributed as email, there will certainly be people who won't do this upgrade; I'm highlighting the contrast between the need for this set of technologies (SPF, DKIM, DMARC) and the utility of an old-school open web where the barrier to entry is low and anyone can participate.

We have seen a massive erosion of the latter aspect of the web in the past few years, and I think it's useful to frame conversations in terms of that loss. The web used to be fun, and now it's become, more than ever, a professional enterprise. You often can't stand up a website without having to buy into Cloudflare's DDoS protection or something equivalent. I think this is absurd, and it's not the only such case, though these changes are obviously reactions to how usage of the web's evolved over the years.

I wonder if we can get the old web back in some way, shape, or form, cause I think we've lost something with the corporatization of the internet.

And for what it's worth, yeah, I think grandma should be able to run a mail server. Why not?