I watched NBC's Olympic News channel from time to time and one commentator with some pretty good background had some insights into the Russian problem. He said that, following the soviet system coming down, the Russian sports system more or less devolved to something resembling the rest of the world - decentralized individual fiefdoms for the individual sports and the spectacular results tapered off.
When Putin came to power, he reorganized national sports, recentralizing with giant camps, directors of each sport, IOW the Soviet system in all but name. It paid off in medals, as it should, with heavy state incentives for both officials and athletes alike. Drugs, he said, were inevitable. It didn't matter if Putin had wanted to keep them out, which is doubtful. He also doubted that the "Go and sin no more approach" which is going to happen would work at all.
Last night, they had on Thomas Bach, the current IOC president. He stated that they would not let the Russians march and carry their flag in the ending ceremonies. He more or less said that it would be a travesty, in view of the fact that 2 of the 4 positive tests in these games were Russian. At the same time, he confirmed that the Russians would be welcomed back into the family, on promise of good behavior, of course...