Newer technologies such as Rust fundamentally do not solve a technical problem, but a social one. As you say, anything can already be done reliably and cheaply using existing tools and chips _provided you already know the field_. What the new tech brings in is "knowledge scalability" - one can reuse much more of their experience from non-embedded platform and focus on learning the challenges specific to the MCU environment without having to deal with the incidental complexity of low-level programming.