Is that any different from most other sports that hold World Championships?
I mean, the recent Athletics World Championships were full of surprise winners, from Oblique Seville, Jimmy Gressier, Cole Hocker, Isaac Nader, Geordie Beamish, Lilian Odira, Ditaji Kambundji and Juleisy Angulo - all athletes that performed on the day when it counted.
Flyaway events far from the regular hosts do seem to see a higher probability of surprise results, perhaps, but otherwise the course is the same for everybody. The World Championships in cycling are more like a 6th Monument than anything else, and the course varies year on year. A rider may have several Worlds that they can target in their career, or they may only get two or three. That's part of the fun. Some World titles are worth more in the eyes of the audience than others, but the same goes for monuments. I can tell you all about the Mendrisio Worlds off the top of my head, but I can't even remember who was on the podium behind Cavendish in Copenhagen - but they both get to call themselves World Champion.
And when you go back through the annals of world champions, there really aren't that many "who?" figures that appear (although in Doha we did almost have Tom Leezer in the rainbow jersey). I mean, the only winners in the last 20 years to not have also won a Monument are Cadel Evans, Thor Hushovd, Rui Costa and Mads Pedersen. And Evans has won the Tour de France. So the format isn't exactly churning out undeserving champions. Besides, often somebody that wins in something of a surprise goes on to become a major factor in the future too - Óscar Freire in 1999 and Marta Bastianelli in 2007 spring to mind - whereas somebody who burns brightly but briefly seems like a shock champion but in reality was not at the time - Romans Vainsteins being the most obvious example.