We should mention in passing that the very exhaustiveness of the OED makes it completely unsuitable (in the present context) as an accurate representation of the English language, since 90% of the senses listed are unknown to the majority of educated native English speakers (Winchester 2003).
our model cannot be expected to provide a faithful prediction of the evolution of the OED, since we assume that the set of word senses in a dictionary is an approximation of those available to people who create new senses for existing words.