> vast majority of MS Office users would never need the features that LibreOffice lacks

Except for Excel. Excel is truly amazing software and there isn't anything to replace it for many people. I use Python now for my number-crunching, but I used to use Excel extensively when I worked in quality assurance and didn't have access to Python. No way that LibreOffice's spreadsheet can replace it, except for the most simple of spreadsheets. At least not today.