Hi! I'm one of the co-authors of ActivityPub, and I agree with you. I wrote a very out-of-date writeup about bridging ActivityPub and P2P networks some time ago:
https://github.com/WebOfTrustInfo/rwot5-boston/blob/master/f...I think you'll find it agrees with your assessments. DNS and SSL Certificate Authorities centralize an otherwise sensible decentralized system.
It's out of date because work has continued. Here's some hints as to how we can improve the situation:
- Decrease importance of server you're on by allowing easy account migration. One easy way to do this is to use mutable data to represent your activitypub profile in a content-addressed store... you can look at mutable links in IPFS as an example (the work that we're doing on Datashards is also relevant). (ActivityPub actually does support other URI types that are not https so this is no problem...) Don't like the server you're on? Update your actor profile to point its inbox URI at another place.
- Support hosting over more p2p, easily self-hostable, NAT-punching and secure systems where you know you have a secure connection because the name of the server is actually the fingerprint of the key. That's actually what tor .onion servers and I2P servers are. There's no reason you can't run ActivityPub over such servers, and some people do, but it isn't widely supported because...
- ... because of the way we've chosen to do names. The right answer isn't webfinger (which isn't in the ActivityPub spec but is what's popularly deployed), it's petnames: https://github.com/cwebber/rebooting-the-web-of-trust-spring...
- And now you need a way to handle anti-abuse in a system that doesn't assume that domain names and instances are all too important. OcapPub outlines some of that (sadly unfinished, but the core ideas are there) https://gitlab.com/spritely/ocappub/blob/master/README.org
- On top of all that, maybe add store and forward messaging to support nodes being offline. This can be done and we have plans but I need to write them in a more visible place.
So in short, as one of the main authors of the biggest fediverse specs out there, not only do I agree, work is happening.