Cycling is a bit special as a longer endurance sport. There's more to be gained from marginal benefits. That said, cheating is very wide spread. It's a constant race between athletes and analysts. You often can't detect a new strategy of cheating until someone is physically caught and then you can develop an analytical method to do so. Lance Armstrong was caught not by the technology of the time but by revisiting blood samples which had been stored. Athletes may content themselves with microdoping where they use very small doses of drugs or reserved blood to evade detection limits. It obviously is less effective, but they're looking for whatever edge they can get. With small alterations it becomes difficult to distinguish between artificial enhancement and genetic anomalies. If you don't hear about people cheating I think it has a lot to do with them getting very good at it.