Perhaps, but I think it's more likely that the only feasible option was to use VBA with excel, and excel is the "default" spreadsheet application used everywher

Perhaps, but I think it's more likely that the only feasible option was to use VBA with excel, and excel is the "default" spreadsheet application used everywhere. It nearly the same reason why JavaScript became the default front end language thanks to Netscape, which was the "excel of browsers" during the dawn of the internet.