I hope your skepticism is appropriately language-specific. For example auto-vectorization of FORTRAN code has a long, successful history (the Cray 1, and X/Y-M

I hope your skepticism is appropriately language-specific. For example auto-vectorization of FORTRAN code has a long, successful history (the Cray 1, and X/Y-MP were basically FORTRAN machines) due to its memory model and vector affordances. With C, C++, Rust and other such languages of course it's very difficult.