The excitement around Java existed for two reasons: many people were new to the ideas in Java, and many people were learning it for the first time. Now, every programmer knows about Java's ideas (with the possible exception of interfaces which aren't in Python) and the number of people learning Java is capped at the number of kids being born. If Rust is successful then eventually every programmer who wants to learn it will already know it, and every programmer will know how to use a borrow checker. The nobody will post "made in rust" stuff on HN, but that will be an indication of Rust's victory.