Calc is really not an adequate substitute for Excel if you need to use VBA macros - which might be coming from your customers! And in the wild I see plenty of older Excel documents (before 97) which I don’t think are compatible with LibreOffice. Obviously this isn’t an ideal situation but historical data around prices/etc from the 90s are often stored as old Excel binaries.
In general I think using Calc (or Google Sheets) instead of Excel is a bad idea for a business. Word processing and spreadsheets - sure (although there might be some things specific to Word/PPT that I am not aware of). But Excel is a very specific piece of software and should not be thought of as a general “spreadsheet tool.”
Calc has several options for languages to use for macros, for instance Python – I'm not certain about VBA support, but it would seem that many industries are slowly migrating to Python anyway :
The point is that VBA macros are portable across Excel but not between Excel and Calc. Calc does not support VBA macros. As many businesses need to consume spreadsheets with VBA macros, and since porting VBA to Python isn’t sustainable, Calc is simply not a good enough replacement for enterprise.
I am not sure that one anecdotal blogpost supports the idea that industries are moving from Excel to Python. It is more likely that people are productionizing Excel spreadsheets with Python these days, instead of C++ or Java.
I am not arguing in favor of Excel! I hate Excel. I don’t have it installed on my personal devices. I never use Excel unless I have to. I am saying that Excel does specific things that are widely used in industry (especially finance and industry) which are not supported by Calc and that Calc is not a good replacement for many businesses.