Just look at what happened with the Rust foundation. It probably guides a lot of his rant.

That does not follow. Languages as large and successful as Python and as small and up-and-coming as Zig have had foundations for years, despite both having a primary lead developer and tastemaker.

This rant really does come off as an embittered “I refuse to leave my project for future generations because I hate them.”

Again you're making this up. That's not what the message reads. It literally says the future of Nim is assured because there is both funding and people working on it. He says he doesn't want to partake in community building because ...stuff happened with the diversity mob. It turns out that they've been preaching acceptance while harassing people with different upbringing online.

I think you're giving him far too much credit. His rant was an irrelevant screed about racism and sexism with alt-right dogwhistles like "clownworld", not anything about foundation mismanagement, which is what is happening to Rust.