Such threads turn out to be quasidupes because they are almost always discussions about the project in general, not the specifics of the incremental release [2]. Incremental releases generally aren't SNI (significant new information) [3], but are rather occasions to talk again about the project as a whole. There's nothing wrong with that! It's great, it's fun, it's perfect. It's just that moderation is oriented towards nudging HN away from repetition. The default drift is strongly towards repetition, i.e. towards collapsing into the same set of popular, repeated topics. That's a failure mode for the site, and moderation's function is to keep nudging the system away from its failure modes.
I get that it's super frustrating when a project that you are interested in gets downweighted off HN's front page. That's why I'm writing such a long explanation. The moderation orientation is basically the opposite of the individual user's (which is why moderation is necessary in the first place). We have to worry about the site globally, while (and so!) individual users can focus on the things they like and care about, as they should.
If we didn't moderate follow-ups this way, HN's front page would be dominated by repeated discussions about the most popular topics. That would be bad for two reasons: repetition goes against curiosity [4], and it would leave less space on the frontpage for other topics—and frontpage space is the scarcest resource we have [5].
When we moderate this way, it's not a judgment against the project itself or how wonderful or interesting it is. It's a global optimization [6]. Unfortunately it ends up with most people feeling that their favorite stories are under-discussed on HN [7], because they are—there's never enough space. The important thing to realize is that people feel that way about every topic on HN. Even Rust hackers probably feel that way.
[1] https://hn.algolia.com/?dateRange=all&page=0&prefix=true&sor...
[2] The previous long explanation about this is at https://news.ycombinator.com/item?id=23071428.
[3] https://hn.algolia.com/?dateRange=all&page=0&prefix=false&so.... I'm not saying incremental releases aren't significant—of course they are! But the definition of SNI in this context is a little specialized: it means information capable of sustaining a substantially different HN discussion than the last one.
[4] https://hn.algolia.com/?dateRange=all&page=0&prefix=false&so...
[5] https://hn.algolia.com/?dateRange=all&page=0&prefix=true&que...
[6] https://hn.algolia.com/?dateRange=all&page=0&prefix=true&sor...
[7] https://hn.algolia.com/?dateRange=all&page=0&prefix=true&que...