From history, the cyclists that have got caught hasn't exactly been busy with the latest state-of-the-art in doping.

Most fancier methods have been introduced by countries trying to optimize the amount of medals at a world championship or Olympic Games. And it is more probable to be in track-and-field, weight lifting or similar. I kind of get the feeling that the most advanced methods are used in sports where you compete individually. It may be hard to try too advanced stuff in cycling, where most cyclists are parts of teams.

I think a lot of cyclists have realized that the big problems in TdF turns the public away. And with them the sponsors. And without sponsors, there will not be any food on the table. There is a big difference using doping when everyone around them didn't care, and when the press and police are hunting them actively.