Survivor host Jeff Probst talks to Yahoo about endurance - both his and the show's - over the past 25 years. (Photo illustration: Yahoo News; photo: Robert Voets/CBS via Getty Images)As Survivor approaches its landmark 50th season, the inevitable question hangs in the air: Can the reality juggernaut really keep going forever? The show has outwitted trends, outplayed rivals and outlasted almost every other series of its era on television, redefining the reality genre and our understanding of what it means to compete.