> I think it's telling that whenever someone raises concerns about any element of Rust, no matter how constructively (...)

I'm far from a Rust expert, but to me if someone is whining about how it is hard to track lifecycle rules of an object because they are passing it through long chains of function calls across all sorts of boundaries, what this tells me is that you're creating your own problems that you could avoid if you simply passed the object by value instead of by reference. I mean, if tracking life cycles is a problem then why not prevent it from being a problem? Not all code lives in the hot path. I'm sure your performance benchmarks can spare a copy somewhere.