You know what else is common in the games industry? C# and NDA's.

C# means that game development is no longer a C/C++ monoculture, and if someone can make their engine or middleware usable with C# through an API shim, Native AOT, or some other integration, there are similar paths forward for using Rust, Zig, or whatever else.

NDA's means that making source available isn't as much of a concern. Quite a bit of the modern game development stack is actually source-available, especially when you're talking about game engines.