There are many, many factors that need to be taken into account when asking "will this technology succeed" and only one of those factors is "is the technology g

There are many, many factors that need to be taken into account when asking "will this technology succeed" and only one of those factors is "is the technology good/ better than what exists now". Familiarity is a huge one that impacts adoption. There's many other factors discussed. In the book The Diffusion Of Innovation there are two great examples given. The first is a health official trying to convince a town of people to boil their water in order to avoid infection. They utterly failed to convince anyone to do so because the concept of 'germs' was totally unfamiliar to these people, and the need to boil water conflicted with their cultural conception of the issue. The other is dvorak - a keyboard layout that is, by some metric, objectively better than QWERTY. And yet adoption barely exists. The reasons rust is not being used to replace C everywhere are many - Rust is young, many people do not want to learn rust, many people do not care about software security, rust has an unfamiliar syntax/ concepts in it, rust has a younger ecosystem, etc. There is also the issue of liability in software. If I write an internet facing text-parser in C, and it's full of vulnerabilities, I am not liable. My negligence in technology choice (and I do consider it negligence) does not impact liability, unlike any other engineering discipline. So why change?