Toughest question out there. IMHO there will always be people to replace those banned for years. There are so many riders just outside that top level. Banning people just takes someone out and puts someone else in who is just as likely to do it. Same with teams, coaches, and maybe even sponsors. The second you say you will fine sponsors they are gone. Why take the risk?
The culture has to change and I do not know how that can happen. I do not think it is as shameful as others here think it is to be caught. It is more like . . . sucks to be you, you got caught (all while knowing they did it as well)