For the longest time, searching for Ballista linked to its old archived repo that didn't even have a link to the new repo. There was no search result for the new repo. This misled people into thinking that Ballista is a dead project but it wasn't. It wasted so much opportunity.
I don't think it's a fair criticism of Ballista to say that it failed in any way. It just looks to need substantial effort to bring it on par with Spark. The performance benefits are meaningful. Ballista can then not only take the crown from Spark, but also revalidate Rust as a language.