Anubis is not meant to fully stop bots, only slow them down so they don't take down your service. This kind of bot detection is meant to prevent automation.
I think the author misdiagnoses the problem, and the proposed solution simply hides the centralization instead of removing it.
The reason AWS is expensive is not because of IPv4, or the datacenters. It's mostly in their software/managed offerings, and the ability to quickly add more servers. If you are a "serious company" and you don't want to pay AWS or a similar company, renting a rack and colocating your own servers (either within your premises or in a datacenter) is doable and done by lots of companies.
I disagree that certificates have caused centralization, and they're not something separating the haves and have-nots and are in no way comparable to having or not a mainframe. HTTPS becoming pseudo-mandatory didn't push people into having their own (sub)domains, which is nowadays the only requirement to obtain a certificate. It already happened out of convenience.
The other point of centralization mentioned is DNS, which tailscale doesn't avoid at all. MagicDNS still relies on the ICANN root, as does the tailscale control plane. And if all you wanted was a free subdomain, there are plenty of people offering that.
If you are behind CGNAT, tailnets aren't particularly less centralized, as traffic has to flow through the DERP servers. I doubt tailscale can keep providing these free of charge when the volume is in the tbps instead of the gbps.
I agree that tailscale (and similar solutions) help in the last remaining case, which is accessing your computer that is behind a NAT. I even think they could reach the dozens of millions of users. This is, in my opinion, not enough to claim the title of "the new internet".
> Git Operations is experiencing degraded availability. We are continuing to investigate.
https://www.githubstatus.com/incidents/n07yy1bk6kc4