An overview for the reasons that more recent languages (Rust, Go) have avoided the full-on object-orientedness of Java, C#, et. al. Traits and interfaces allow for polymorphism while avoiding the problems of inheritance - they’re not hierarchical, so they avoid issues like the diamond problem that result when implementing new objects that don’t fit easily into the existing hierarchy. Non-hierarchical structs also avoid the bloat of carrying around unnecessary parent fields.