"only", when 99% of the people are perfectly well served with the featureset of yesterdecade's LibreOffice suite, the three problems being the network effect (if everyone else is on another "network" or standard, you're forced to as well), that it looks like 2002, and that they have to spend 10 minutes on the first day to figure out that some buttons are in different places (I'm lost in Office nowadays, it really is just a matter of habit and not that either of them has an inferior layout). With the only functional defect being "it looks old", a modern style is what you pay 150€ every year for when buying into the Office monopoly. Except as a student: they're happy to help you gain the habit and experience the network effect.
I guess this is why Google Docs has been the first to make a dent: you seamlessly download the software to render the file format upon pageload, so there's no network effect on file formats anymore. Add a modern look, reach into your pockets to make it free until you've established a good market share, advertise for it in your already popular products (costing them nothing), et voila
