It is laughable that cycling is now "cleaner" than T&F. I would argue they are the same.
UCI (governing body for cycling) does appear to be tougher on doping, and as such, more athletes are caught. By and large, cycling is a "first world sport." Poor people don't cycle. As a result, the culture, information, and resources to dope are much higher in cycling.
Another item is that ASO, who govern French sports, are very anti-doping, and since the biggest event in cycling is the Tour, the ASO has more push than maybe they should have (which again is why cyclists get busted regularly).
This is all cyclical. In 1998, you have Festina scandal. This supposedly "cleansed" cycling of doping. The very next year, you have the reign of Armstrong. I think we all know "how clean" cycling was.
Then you have Operation Puerto, and this exposed the dark underside of cycling, and now it would be clean (Ullrich, Basso, and others busted).
In the very same TdF Landis wins, and is busted for drugs. That'll clean it up.
The next year Vinokourov puts on an exhibition, and gets busted late in the race. That'll clean it up.
At the Olympics, Rebellin, a single day stud, gets busted for CERA. That'll clean it up.
And so on. Every year, big busts. Every year "it's now clean."