Anecdotally I can tell you it does not amount to a loss in productivity. Cargo caches built deps so the cost is really only paid once in a while and the advantages of rusts type system are a boon to productivity.
It can be slightly annoying -- compared to f.ex. OCaml with its lightning-fast compiler -- but in practice incremental recompilation is much faster than a compilation from scratch so it rarely irks me that badly.