Isn't this common in sports? If you're caught intentionally cheating even once your entire career's achievements are invalidated.
Titles/records are stripped from events where they are proven to be doping/cheating but that's usually it. Athletes are then usually banned for a period afterwards.
It's just that the conclusion of the investigations into the allegations that started early in the major success portion of his career was that he was cheating the whole time of his biggest successes.