When did software devs lack the power to write trading tools? The issue is that the traders had the knowledge and wrote their ideas into a spreadsheet which was not only maintainable for them but easily extensible. I cannot overstate that second part. They become spreadsheet behemoths because it's trivial to make them do that one extra thing (at least for the first fifty or so features).

Probably when the IT peeps in finance believe that the problem with spreadsheets is their speed. As the fundamental problem of spreadsheets in finance has absolutely nothing to do with their speed, this may take a while.