My Productivity tanked when using Rust but I have not written 20k Loc yet. Ownership gets messy when you have a complex mutable application model (worse: oop written according to SOLID principles). At that Point,Just give Up and use ref counting (which you would use in c++ anyway..).
I still like to believe that the upfront cost will be offset by the lower long term maintenance cost for some types of software. Except, that that is not always the case for gamedev where shitty code can still make good and successful games. You may miss a deadline, but if you are not going to maintain the code base for 20 years, so why spend the effort on quality code?
