You don't spend developer time "thinking" about lifetimes as you write Rust, it becomes totally automatic, no more than you spend time "thinking" about functions in C#. The benefits you get far outweigh the negligible overhead, providing things like data race prevention across threads in addition to memory safety with incredibly low overhead. Modern GCs are faster but they're by no means free, and totally unnecessary if you just give the compiler the information it needs to do its job statically instead of continuing to strap more rockets to the GC rocket-powered horse. It's the fastest horse but it's still a horse, not a car.
> Modern GCs are faster but they're by no means free, and totally unnecessary if you just give the compiler the information it needs to do its job statically
These are not mutually exclusive.
(1) A GC'd language can still do static analysis at compile-time or JIT-time to avoid GC all-together when possible
(2) GC'd languages can have RAII/static-scoping capabilities such as immutable value-typed (non-ref) structs which require initialization and using{}/after blocks for scoped lifetime
(3) GC'd languages can have owned-object semantics like C#'s Span<> to avoid GC
(4) You can use unsafe and pointers and GC'd languages a well
So you can still program with an eye toward efficiency for any code that shows perf issues using many of the same constructs you do in Rust, in a GC'd language -- but be able to fall back on GC when lifetime issues are complex or hard real-time perf is not an issue.
Again, I'm not bad-mouthing Rust at all -- I'd far prefer it to C++ in the context where the latter is appropriate.
Try to write a sizeable Gtk-rs application to see how automatically it gets if you don't create your own clone macro to deal with all the Rc<RefCell<>> instances, like the Gtk-rs samples show.
I’m not sure a single example of a C wrapper not idiomatically designed is a good example of the potential of a language. It’s like pointing to the source for any given STL implementation as quintessentially C++ coding style. RefCells tend to be considered an anti-pattern AFAIK since they leave invariant checking to run-time. It's meant as a hack/patch if you can't actually design it idiomatically for some reason, such as in this case, FFI to a C programming model.
I can point to other UI examples, like game engines written in pure Rust, using array indexes with clocks on access to invalidate possible use-after-free accesses with outdated indexes.
