Other languages don't do without them, the costs are just worse in Rust (and C++). Go for example consciously tried to avoid shipping generics and was forced to implement them by community pressure. They now pay the same kinds of monomorphization costs as C++ and Rust because the alternatives have greater runtime costs. Go is simply a faster-compiling language overall though and the problem is less noticeable. Macros are similarly ubiquitous in other functional languages, but most of them aren't compiled or meaningfully optimized.

Rust is complex, highly expressive, and does a lot of optimization. None of that's good for compile times. C++ is even worse because of how awful the template abuse gets and the amount of duplicated code that's fed into the compiler from how #includes work.