My personal take, it is all about the fans.
Look at all of the other sports with doping problems. Baseball and Football come to mind. All of these sports are primarily about Entertainment. Making money for sponsors and pleasing fans.
That being said, IMO doping will continue until WE the fans get up in arms. Stop watching, writing letters etc. If teams start having sponsors backing out due to bad press or fan boycotts, then maybe teams will start doing something about it.
-D