And Adobe PDFs are not the same as PDF/As and yet somehow the world still turns and PDF readers of all sorts find their way around.

I’m not saying OOXML is a great standard. I’m saying it’s a fine standard for the specific purpose of having a format that Microsoft can no longer claim IP rights over, so that should Microsoft suddenly feel pressurised to remove Office functionality from Europe, Europe still has a workable solution that’s compatible and interchangeable with the 99.9% of all editable document files sent around.