The tolerance of increased volume/frequency is markedly higher in those receiving exogenous anabolics in supraphysiological doses. I'd be really surprised if a successful Eastern European weight lifting team were not doing this. The difference between 800 ng/dL and 3000 ng/dL is massive.
Olympic lifting itself is also more about technique and explosive power, with hypertrophy coming as a disadvantageous side effect, since these guys are usually in weight classes. Not sure that it would necessarily carry over even if they were clean.
That being said, I agree that hitting a muscle group once a week as many do these days is less than ideal. I never really started to make progress until I started to hit groups 2-3x a week. I'd never do multiple times a day however. Additionally, although I've increased frequency, I haven't really increased volume. I can't seem to find it now, but I was reading a study recently where they had trained individuals either do X volume once a week or X volume split into 3 workouts, and the latter program was significantly more effective.