>Is there actually a third option? I'm wondering of the author simply misunderstands Ethereum.

The issue is Urbit bills itself as 'decentralized' but isn't. If you buy Ethereum and disconnect from the Ethereum network your Ethereum doesn't go away but with Urbit you're just running your own server. Urbit should just call it what it is, a software stack. It's not 'decentralized' or an 'OS'. It's a software stack that requires a conventional OS and server.

"Just running your own server" is the proper meaning of "decentralized" [0].

Urbit has a literal operating system named Arvo built on top of a virtual machine named Nock. The terms are used technically; it's not trying to compete with Windows.

[0] https://en.wikipedia.org/wiki/Decentralized_computing

That article goes straight into peer-to-peer and file sharing so it is hardly surprising that most people expect a decentralized platform to exist primarily to eliminate SPOFs, i.e. provide redundant access to data of down peers.

I’m curious as to your definition of decentralized here. It seems you’re using the term to mean “global commons”, when I generally would use the term to mean something more akin to “permissionless” or “exhibiting a resistance to control via a singular entity or small group of entities”. Urbit is certainly decentralized by either of the two latter definitions, though a particular Urbit server surely wouldn’t constitute a global commons, which seems closest to your definition.

there is peer-to-peer decentralisation and federated decentralisation.

Maybe Sia/Filecoin/etc is a better example; every node does not store a copy of every piece of data but the blockchain is used to coordinate storing a reasonable number of copies. You could imagine using a blockchain to coordinate computation in some kind of decentralized attack-resistant way although I've never seen this done and maybe it's not feasible.

I _think_ there is a third option, hosting in IPFS.

Regardless whom does what, I think that a autonomous decentralized website should be possible to be ran on crypto services.

A server could use either service for storage (and sharing). You can't run Urbit's operating system on top of either, the part that executes code is missing.

Not on Solana. In fact, people are already writing software (metamask) that uses on chain computation, file storage with ipfs and even could support an blockchain controlled CDN for distribution (https://media.network/).

All with gas prices that literally fractions of a penny and 50k+ transactions per second.

The main problem here is that it's Solana, so in essence even more controlled than the wider internet

At the cost of decentralization.