FWIW, transitively-safe Rust is quite uninteresting as an actual programming language, since you can essentially only use some arithmetic and simple user-defined data types. There's no IO and no core data structures like Vec: `unsafe` is designed to be used as a building block to create safe interfaces and the distinction between safe things implemented in the language itself and safe things implemented in libraries (especially the standard library) is fuzzy... and even then, the compiler can be regarded as one huge `unsafe` block.
Of course, what you say is perfectly true, the Rust language itself has no threads or concurrency, and hence is automatically dead-lock free.
Yes, it's somewhat banally true, but it's an important subset of the language because the guarantees of transitively-safe Rust represent a baseline for what you can ultimately guarantee in the language. Work like Patina (ftp://ftp.cs.washington.edu/tr/2015/03/UW-CSE-15-03-02.pdf) is useful for that reason. Transitively-safe Rust may also independently fulfill a useful role in the language; e.g., it is a candidate for the subset acceptable in constant expressions.
Of course, what you say is perfectly true, the Rust language itself has no threads or concurrency, and hence is automatically dead-lock free.