Yes I know. I see the same statement every single time this conversation comes.

Let me ask this: hypothetically if they wanted to, would it be possible for Zig to add a language feature called Interface which provided to the user "...an easy way of creating one".

Creating an interface is fairly easy once you know how. I would say that it is as easy as in rust for a beginner. You get used to it and I don’t believe it needs a special keyword.