The other way would be if you personally know some movers and shakers. I think that's also quite common. From time to time it's so obvious you're going to see speakers talking about projects or subjects that couldn't possibly have gotten up there on their own merits. They're not terrible, but they're sure not doing stuff that's significantly cooler than what most other people in the community do.
The third option is that you're so well known in your community that you technically don't need corporate sponsorship or personal connections, but those probably go together anyway more often than not.
Everybody else is going to have a bad time. Im uncertain if this is a bad thing per se, but it's also easy to see how that precludes the participation of a lot of people who could make a nice contribution. But if speaking is what you absolutely want to do, you could conceivably work your way up from smaller to ever-bigger conferences.