Sediment in a fine bottle of Bordeaux is not MOG. The very high end vineyards can afford the labor to sort the grapes and include only the ones that are up to standard, while eliminating most of the other debris. Even in vineyards where MOG ends up in the ferment, that stuff precipitates out during racking and clearing.
In a fine, aged bottle of Bordeaux (or a California Cab) you get sediment forming from the precipitation of tannins. During aging the tannins slowly aggregate and drop out leaving the wine smoother and more refined. This is natural, and in fact, desirable, but it is also why these wines need to age a decade in most cases before they start to reach their peak.