It's not a matter of whether the internet is global, its who your audience is... if you audience is primarily in developed nations, then the rest of the world isn't much of an issue.
Much of the internet is a business, not a passion project. There are plenty of businesses that are completely OK with being inaccessible to users on 2g/3g in the developing world.
"Bill, phone calls are so 1992, they hired a web dev to create online polls"