The problem is that I maintain other people's code, and I don't want the language to add all those extra things. It's a big cognitive load to maintain, and leads to bugs in production software that is hard to debug.

The julia docs mention that Fortran arrays can be indexed with various starting numbers. I've programmed and maintained millions of lines of Fortran over 20 years and I've never seen anybody use anything other than 0 as the starting index.