It’s very possible there’s something I’m missing, but my instinct is: yes, it very probably would. If data can be presumed immutable, a whole lot of ownership rules could be relaxed to scope and cycle counts which could be verified at compile time with no runtime penalty. The whole premise that data needs to be borrowed is explicitly to guard against conflicting views of shared state. Such conflicts can only arise by mutability of shared state. Rust’s solution to that is to limit mutability to only one part of a procedure at a given time. If nothing can mutate state at any point in a program’s lifecycle, that tradeoff can be expanded to basically whatever facilities the hardware/compile target affords.