Agreed, it seems weird to me to avoid garbage collection in a high level language. It is one thing to use escape analysis to avoid creating garbage, but mallocing every object is going be slower than a well tuned GC.
I would say that in practice 80% of the values go on the stack, 18% in Box and 2% in an Arc/Rc. That's why Rust code tends to be fast: the common cases are really easy to represent with the borrow checker, so a hypothetical GC doesn't have to perform escape analysis to see if it is ok to specialise those allocations, while the more uncommon cases can still be represented, albeit more verbosely than a GCd language would need.
