Largely because Rust has grown massively and Mozilla isn’t even close to its biggest sponsor at this point.
Azure, AWS, Google Cloud are all major Rust sponsors at this point. It doesn’t make sense for Mozilla to remain a major sponsor for a product that almost certainly can and will exist, and likely flourish even more, as a more independent project.
At this point Mozilla’s ownership of Rust would likely only cost resources and serve to limit the growth and development of rust.
Azure, AWS, Google Cloud are all major Rust sponsors at this point. It doesn’t make sense for Mozilla to remain a major sponsor for a product that almost certainly can and will exist, and likely flourish even more, as a more independent project.
At this point Mozilla’s ownership of Rust would likely only cost resources and serve to limit the growth and development of rust.