> but 1-based indexing is more convenient for about 99% of the code written in Fortran, Matlab or Julia.
You could make the same argument for octal literals over the scary hex numbers with letters mixed in. 1-based indexing was invented by mathematicians using conventional notation without fully appreciating the problems it causes in computing systems. There is no reason to continue the insanity.
It has nothing to do with not fully appreciating the problems it causes computing systems - many of these notations predates the existence of computing systems or even the though of them. Mathematicians use both zero based and one based systems, sometimes due to mere convention but more often where it is natural to the problem domain. Natural notation has a lot of power to help understand your results. I agree sometimes it is a pain to translate to a physical representation in a computer, but it's not like "just always use zero based" is a good enough answer either.
You could make the same argument for octal literals over the scary hex numbers with letters mixed in. 1-based indexing was invented by mathematicians using conventional notation without fully appreciating the problems it causes in computing systems. There is no reason to continue the insanity.