Would it be impossible for Excel to allow coding in multiple languages? I totally get that there's a huge (disturbing) amount of business critical stuff using the current scripts, but they really should move on to something more modern.
Multiple-language runtimes typically don’t get popular - people just end up choosing one language and standardizing on it. See for example Windtows Scripting Host: you could always use Javascript with it, but almost nobody ever did in practice. After a while, typically the vendor sees other languages as a drag on development, and they get dropped in favour of the main one.
Retrofitting a multiple-language runtime under VBA would likely be a big endeavour, and in the end most people would probably stick to the established language anyway.
Microsoft pretty much built it (would allow any .net language to behave like VBA, with an integrated IDE and ability to save code inside the document). Then they killed it. I think that was a huge mistake from a productivity point of view, and also to get a fighting chance to retire VB6.
