Good news! There's 3 or 4 billion of us connected to the internet!
Bad news! These were the easy ones to reach - basically the rich and moderately well-off. But the real challenge is to bring content to people with poor infrastructure, no connectivity, or even outright censorship (not mentioning war zones), and that's another 3 or 4 billion people for whom accessing Wikimedia content is a drag - both in terms of time and resources.
While this problem may seem like one for World Governments, the UN, or some random billionaire to solve, there's actually a bunch of solutions and steps you, as a Wikimedian (no matter the project), can do to help. Also, they're pretty painless (and free), so it's not like you won't be able to do it after you've heard of them.
People will better understand what it is like to be an offline reader (or even editor), and change their editing behaviour accordingly to improve the value of content accessed offline.