Big Show is main eventing WWE’s Survivor Series pay-per-view with Randy Orton because there’s a renewed effort within WWE to put larger or bigger wrestlers in the spotlight. This is the reason for Show being pushed and why we’ve seen more of Luke Harper and The Great Khali lately.
There’s a feeling that Daniel Bryan was on top for a few months and WWE’s pay-per-view buyrates have been down during that period. The feeling among upper management is that Bryan isn’t a larger than life wrestler and that’s what fans want. They feel a guy like Bryan should be on the mid-card having great matches.