This is the correct answer. Surface codes, like the ones discussed in the article, are essentially a way to simulate a kind of topological quantum computer on other architectures.
Nobody has yet built a topological qubit though, but Microsoft has claimed to be close for at least 5+ years now. On the other hand, TQC is supposed to be able to scale much faster, since the way in which you create a new qubit (by creating several anyons) doesn't necessarily require additional hardware - you could move the anyons for one qubit out of the way, and then use the same device you used to make them to make another[0]. Of course more hardware for manipulating additional qubits simultaneously may be desired - but the point is that the scaling problem is theoretically easier for TQC, even if creating the first qubit seems to be much more difficult.
They are not immune to all forms of errors - for instance, cosmic rays could cause unwanted anyons to form. But they are immune to most typical errors.
[0] This is a bit of an oversimplification. When talking about theoretical TQC, we are often talking about actually moving anyons confined to a 2D surface around. However, in the real world, the medium on which this happens is very disordered, so due to Anderson localization, anyons are actually trapped where they spawned. So this is where Majorana fermions and nanowires come in as a realistic approach where anyons can be moved, or alternatively, "measurement-based TQC" which relies on teleporting anyons instead of actually moving them.
You can use NFT's as decentralized permission tokens for access to decentralized databases.
Abstract all the world's resources and how they're converted between each other into one big linked excel table. Everyone wants to know how resources are moving around, but nobody can be trusted to host "the diagram of everything". Different parts of the excel table correspond to different resources in different places, and have notions of data sovereignty over their resources in the table, with areas of joined access between separate entities along boundaries where they exchange resources.
Obviously you'd use something like soulbound NFT's, so its harder for people to sell off write permissions. But you could use all sorts of Sybil protection techniques.
It seems like one possible starting point for a decentralized communism.
I'd like to point out that Urbit ID and Urbit OS are two separate products. Many HN commenters object to the ID system for one reason or another, rather than the OS itself (which may just be because it requires substantial time investment to get to the point where one could criticize the OS).
Urbit OS uses Urbit ID primarily for packet routing and peer discovery. If you already know the IP of whoever it is you want to talk to, packets are direct. If you don't know the IP, you ask their sponsors. In NAT'd situations, sponsors end up routing the packets as well, but this is a limitation of IPv4 rather than Urbit.
It is a simple mathematical fact that hierarchical peer discovery and routing is faster than a purely flat network topology. UX is king for adoption, and an "alternative internet" that is slower than the existing one would never gain mass adoption.
So if you care about actual adoption, you're pretty much forced into using hierarchical routing and peer discovery. At least initially.
Ultimately, your ship has final say over what you think the PKI looks like. You download the state of the PKI from the blockchain, but you have final say over how you interpret it. The default software run on every node, from comet to galaxy, is identical. It is probably quite easy to change a few lines of code and use whoever you want for peer discovery and packet routing. Treat a planet as a galaxy if you want. In that sense, galaxies and stars are just default suggested infrastructure nodes, and are in theory totally optional.
There's nothing preventing anyone from building a completely alternate routing infrastructure using Urbit OS that is entirely detached from Urbit ID. As long as the message protocols remain sufficiently similar, such networks could also communicate with one another. The PKI can trivially be forked, the rules completely changed, and you can set up your own network. You can also build virtual networks atop the existing one. If you want a flat network topology at the expense of latency, you could e.g. use some form of DHT routing.
Thus far, the network is too small for anybody to bother building such a thing. But it is easy to imagine many networks, with their own home-grown routing protocols, and their own ID systems, in a future where P2P computing of the sort exemplified by Urbit takes off.
Thus, I see the hierarchical peer discovery and routing mechanism as a almost-necessary bootstrap and growth hack for adoption, but it is in fact voluntary to participate in, and the field is open for many alternatives to emerge in the future.
It's being worked on. If the plan to use ZK-STARKs to rollup PKI transactions goes through, it should be only a few cents to set up a planet. In the meantime though, it is a major barrier :(
Nobody has yet built a topological qubit though, but Microsoft has claimed to be close for at least 5+ years now. On the other hand, TQC is supposed to be able to scale much faster, since the way in which you create a new qubit (by creating several anyons) doesn't necessarily require additional hardware - you could move the anyons for one qubit out of the way, and then use the same device you used to make them to make another[0]. Of course more hardware for manipulating additional qubits simultaneously may be desired - but the point is that the scaling problem is theoretically easier for TQC, even if creating the first qubit seems to be much more difficult.
They are not immune to all forms of errors - for instance, cosmic rays could cause unwanted anyons to form. But they are immune to most typical errors.
[0] This is a bit of an oversimplification. When talking about theoretical TQC, we are often talking about actually moving anyons confined to a 2D surface around. However, in the real world, the medium on which this happens is very disordered, so due to Anderson localization, anyons are actually trapped where they spawned. So this is where Majorana fermions and nanowires come in as a realistic approach where anyons can be moved, or alternatively, "measurement-based TQC" which relies on teleporting anyons instead of actually moving them.