If you just Rc everything (which I'd count as "abusing Rc") Rust is significantly worse than a language with a good GC. The good thing about Rust is that it forces you to aknowledge and consider the lifetimes of objects. By default things are allocated on the stack, but if you make something global or dynamically handled (e.g. through Rc) you have to do so explicitly. In Rust the compiler has greater compile time information about when things can be freed which means that you need less runtime overhead to check things and if you want to minimize the amount of potentially long-lived objects you can more easily see how long objects might live by reading the code as well as get help by the compiler to determine if a lifetime-based refactoring is sound or not.
If you just Rc everything (which I'd count as "abusing Rc") Rust is significantly worse than a language with a good GC. The good thing about Rust is that it forces you to aknowledge and consider the lifetimes of objects. By default things are allocated on the stack, but if you make something global or dynamically handled (e.g. through Rc) you have to do so explicitly. In Rust the compiler has greater compile time information about when things can be freed which means that you need less runtime overhead to check things and if you want to minimize the amount of potentially long-lived objects you can more easily see how long objects might live by reading the code as well as get help by the compiler to determine if a lifetime-based refactoring is sound or not.