I'd consider structs that implement various traits (to use Rust's terminology) to be more of a 'usual' approach to an object model. You can see the approach with mixins in many scripting languages, Rust's entire object model, Haskell's typeclasses, Elixir and Clojure's protocols, ect. ect.

The fact that you can classify things into a classification tree does not mean that the classification is how things actually work. If it so happens that classification trees work for a problem, you can build them with trait inheritance, but structural inheritance hasn't been that useful IME, so the marrying of both types with classical inheritance just leaves a bad taste in my mouth.