But you do realise that pressuring distributions in that way (when there are still issues with integrating cargo and crates into our existing build systems) won't result in Rust being properly supported right? There will be some hack to get Rust to work "well enough" to build Firefox, and if someone wants to start packaging more Rust stuff then all of the work would either need to be redone or started from scratch.

I'm saying this as someone who has started writing their projects in Rust and has plans to ship said projects as part of openSUSE and eventually SLES. If you cannot satisfactorily maintain a Rust package inside OBS then it's a non-starter. I imagine that many other distributions feel this way. We were burned with Ruby (and continue to be burned by it) and I doubt that anyone is going to jump on the "just auto-generate an RPM for every version of every crate we need" solution.

It's great that Firefox will have Rust code, but I'm not convinced that will make the situation better for distributions. It'll just make the packagers more stressed out.