I've said it misses most of metaprogramming features, not all of them. Reflection can't do the same things as macros can. Macros can transform arbitrary AST to arbitrary AST, reflection can't.
Similar thing with interfaces - while they serve the same purpose as traits, they are nowhere as flexible/expressive. E.g you cannot do blanket interface implementations - i.e. implement an interface for only the classes that implement another interface. You also cannot implement the same interface more than once, differing by generic parameters only. Or cannot define an interface with an associated type member (Scala is another language that can do it).
The discussion was about being higher-level vs lower-level. Rust is a more expressive language than Kotlin. Where languages are used is a different matter, because expressiveness is not the only thing playing role there. Politics and historical reasons are another dimension.
You seem to be missing my point. The point was not about which languages are mainstream (which is highly subjective, hard to measure and also may be an effect of certain politics), but about their level of abstraction. Rust is often placed in the "low level, close to the hardware" bin because it can go low-level very far if you wish to. But it is often forgotten that it can be also very high in terms of expressiveness / abstraction power and offers productivity features not found in many mainstream languages.
Similar thing with interfaces - while they serve the same purpose as traits, they are nowhere as flexible/expressive. E.g you cannot do blanket interface implementations - i.e. implement an interface for only the classes that implement another interface. You also cannot implement the same interface more than once, differing by generic parameters only. Or cannot define an interface with an associated type member (Scala is another language that can do it).