I have upgraded Rust every six weeks. I run `rustup update stable` and wait a minute. Its not a time investment! Rust puts so much work into guaranteeing backwards compatibility so that updating every 6 weeks is an effortless process.

You seem to come from an experience where software updates are kinda sorta mostly backwards compatible. Rust works very hard to actually be backwards compatible. There is infrastructure to check for regressions across the entire package ecosystem, which is run regularly on HEAD and on any commit we think might potentially be breaking before we even land it.