Pro Cycling has survived Operation Puerto, the Festina Affair, and many other controversies that have led to top riders or entire teams being excluded from the sport.
Pro cycling has done better than survive, it has flourished in many markets during these periods.
There will be four teams based in the United States in this year's Tour. That is more than ever before. Cycling in the US has grown tremendously during the darkest period of doping controversies. We now have two tours that have an international draw of talent as well as several one-day events.
Pro Cycling has grown in popularity during these troubles years in nations in Southeast Asia, Oceania, and in the Middle East. The Tours of Oman and Qatar amaze me. That such international talent would find racing in such remote regions is an indicator that international pro cycling is a growing sport.
There was recently a thread that posed the question, "Are there too many pro races on the calendar?" The fact that the question exists does not indicate a shrinking sport.
European nations with lond traditions in cycling will likely always have strong support for pro cycling. Boonen's positives for cocaine have not tarnished his image as a national treasure. Pantani's memory is revered in Italy. Ullrich and Zabel are still German national heroes. Riis is still heralded as a great tactician. There are many more exmaples.
If Armstrong or Contador were to test positive and be excluded from the Tour this year, there would be the opportunity to spin the story into a positive. Contador would be said to have had to dope to beat the 'living legend' of Armstrong. Armstrong would be able to claim that a 39 year old cancer survivor had to resort to methods used by others to maintain the ability to compete. The soap opera would be different, but the story would go on.
This is a good link to an article that chronicles the history of doping cases in cycling:
The list is long, and cycling has endured. When more cases are added to that list, regardless of how big the names of the riders implicated, the sport will continue to thrive.
There is no sport that allows the fans to come as close to the athletes. There is no sport that has beauty and scenery to match cycling. There is no sport that almost every person can relate to in some way, since most people have ridden a bicycle at some point in their lives. Even with it's problems, there is no sport that has the appeal of cycling. For that reason, another huge doping scandal would be able to come and go without doing irreperable harm to the sport.