That article makes the Web of Trust seem like an even bigger mistake. Once you have more than handful of keys in the system the interactions become complex, too complex for good security IMHO.

Does it?

For a key to be considered valid it must be either ultimately trusted, signed by ultimately trusted key or one fully trusted valid key or 3 marginally trusted valid keys.

It seems to me there are only two properties to track and quite easy calculation to do (fizz buzz level).

That's already three conditions, and those spider up to the conditions above.

It's like ACLs. On the surface they seem so easy, but in practice they're a nightmare to manage because you have to track so many dependencies to figure out a simple yes/no question.

There is one assigned property (trust) one relations table (signing key, signed key) and one computed property (validity, the output) and one condition.

I'd be very happy to see a simpler solution to the problem of decentralized authenticity.

Some projects do rely on Web of Trust, for example Linux kernel (https://www.kernel.org/signature.html#kernel-org-web-of-trus...) or Arch Linux (https://www.archlinux.org/master-keys/).