I agree you don't strictly need to update your mental model, but that doesn't make the update itself less expensive. I'd guess most people using Rust and check

I agree you don't strictly need to update your mental model, but that doesn't make the update itself less expensive. I'd guess most people using Rust and checking the changelogs are people who are interested in keeping up with Rust. They are likely to update their mental model because they wish to. And as a result, they often have to deal with these 'expensive' updates which makes it feel like it is difficult to keep up with Rust.