And implementing data structures in any language is hard. It's just a harder thing to do than most things because there's always gonna be a lot of gnarly implementation details and edgecases.
Why make it harder.
> excellent standard library.
The standard library is intentionally bare-bones. They don't want to maintain libraries in std, and want you to use crates.
> wider ecosystem of libraries
The quality of these is quite poor in a lot of cases. People literally make blog posts into crates.
As for the quality of crates, yes, this is the case in any language. Using a library includes the responsibility of making sure the quality is up to scratch. This is not unique to Rust.
To achieve static memory safety.
If you don’t need or want that, you’re probably better off sticking to other languages. Although hopefully, not something like C or C++ which the US government now advises against using for security reasons.
Edit: and even among "interview puzzle data structures", stacks and queues have much simpler semantics than linked lists.
Is a Red-Black tree simpler than a linked list to implement than a linked list in Rust? What about a Fibonacci heap?