It would have taken the same time, if not less, given the extra time for mitigations, trying different optimization techniques, runtimes, etc.

One of the reasons the project was killed was that we couldn't port it to our line of low powered devices without a full rewrite in C.

Please note this was more than a decade ago, way before Rust was the language it was today. I wouldn't chose anything else besides Rust today since it gives the best of both worlds: a truly high level language with low level resource controls.