Imagine you have 100+ projects in java, that became obsolete due to Oracle decision to "improve the language" .
To me, the required effort is not easy to the point that better to invest in migrating the projects to other languages such as Rust.

So I expect to hear for example : "Lets see why we should continue using java"
Instead, you hear : " Oh the new version of java has nice features, lets continue using it".

Then I understood why :

If you start a new language, you are a beginner so if you were a master in Java, then you will not accept to be a beginner in Rust, just like anyone who discovers the language.