The other upside is that Google Docs aren't entirely compatible either. So people are already used to imperfect versions and needing to pass around PDF's if output matters.

The biggest problem I see is Microsoft can only cleanly collaborate with Micrososft and Google with Google. The second you open that docx in Google, all bets are off.

The real downer is the libre's lack of supported online collab, that's pretty much a requirement for business these days.