Rust isn't really new or untested, though. I issue with RIIR isn't Rust so much as the act of rewriting, which carries inherent risks.

I think the temptation to rewrite also reflects how messy and unworkable we let codebasee get— sometimes that impulse is more about the pain of working with the existing codebase than anything else.

To me, the tragedy of rewriting is the underappreciation of why the gnarliest 5% of the codebase is there.

Occasionally, usually because initial requirements were sorely lacking or changed, you can simplify the system via rewrite.

More often, everyone ends up realizing they didn't actually understand that last 5% of edge cases.

And then you've either replaced the working system with a 95% complete solution (so common in modern software) or you produce a system equally ugly once you handle that last 5%.