Most certainly not. Software rewrites usually are well-intentioned and might have benefits. Dental replacements like these are certainly not well-intentioned and only the dentist benefits from them.
Unnecessary rewrites are a way for engineers to benefit themselves (more fun than maintaining existing stable technology, updating resume with new technology) and not the company.
It's not that all rewrites are this way, or that all dentists are corrupt. But both patterns exist.
You make a good point. Though I believe much of the “rewrite it in Rust” hype is about actually improving the security and/or performance of the software being rewritten.
That's the thing, there's always a justification if you want to find one. I don't think most engineers do it maliciously, they talk up whatever risks and benefits are in vogue on blogs or whatever and believe it sincerely enough themselves without ever seriously and objectively weighing the need for it.
