I ported a closed source web conferencing tool to Rust over about a week with a few hours of actual attention and keyboard time. From 2.8MB of minified JS hosted in a browser to a 35MB ARM executable that embeds its own audio, WebRTC, graphics, embedded browser, etc. Also a mdbook spec to explain the protocol, client UI, etc. Zero lines of code by me. The steering work did require understanding the overall work to be done, some high level design of threading and buffering strategy, what audio processing to do, how to do sprite graphics on GPU, some time in a profiler to understand actual CPU time and memory allocations, etc. There is no way I could have done this by hand in a comparable amount of time, and given the clearly IP-encumbered nature I wouldn't spend the time to do it except that it was easy enough and allowed me to then fix two annoying usability bugs with the original.