Rust's ecological niche, besides the affine types/lifetime stuff, is "borrow as much stuff as we can from Haskell/ML without dragging in a language runtime". "

Rust's ecological niche, besides the affine types/lifetime stuff, is "borrow as much stuff as we can from Haskell/ML without dragging in a language runtime". "Without dragging in a language runtime" happens to be a primary requirement for writing bare-metal code or writing GPU shaders. So you have a language that does have a bunch of nice new features (ADTs, acceptably modern type system, etc.) and doesn't have any of the stuff that prevents you from compiling it to random bare-metal targets like GPUs or MMUless microcontrollers.