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/).