I have used excel a lot in my career, but I don't think I have ever created or even seen VBA in any spreadsheets. I think it probably varies a lot by domain, but if I were to guess I would probably say that far less than 1% of Excel spreadsheets use VBA. And a lot of spreadsheets that do are probably good candidates to be rewritten in some other tool.
In my opinion, the reason that Excel has such a commanding lead in that space is more due to familiarity, compatibility, and that Excel is still just one of the nicest spreadsheet apps to use.
In my opinion, the reason that Excel has such a commanding lead in that space is more due to familiarity, compatibility, and that Excel is still just one of the nicest spreadsheet apps to use.