Microsoft claims 1 billion MS Office users. No doubt some/many are pirated, but that gives a sense for the scale of the potential user base for OpenOffice. And from what I've seen, Apache OpenOffice gets around 1 million downloads per week, a steady rate that can certainly continue for quite a while. So even if Apache did nothing, we would get to another 100 million downloads in another two years.
The question is whether we want to glide or really take off?
To really advance among mainstream end-users, people like your mother, this will only happen as average people, not just the techies, learn about open source and are comfortable with it. This means better documentation, especially geared toward newbies.
To advance among corporate users OpenOffice needs better interop with Microsoft Office. Yes, I hate to say that as much as you probably hate to hear it, but it is the reality we (some of us at least) live with.
Finally, we should find a way to extend the OpenOffice brand to the web and tablet editing experience, since traditional desktop PC use is a diminishing proposition.