"The half-life of an irregular verb scales as the square root of its usage frequency: a verb that is 100 times less frequent regularizes 10 times as fast." From Lieberman et al in Nature. An interesting question is to what other morphosyntactic rules this generalizes to, like noun plurals (and to what extent is it influenced by phonetic realization. My guess: not very much.) Pinker and many others knew qualitatively that the less a verb is used, the more likely it is to become regular in a given time period. Now we have the quantitative rule.
"...there is good and bad speculation, and this is not an unparalleled activity in science...Those scientists who have no taste for this sort of speculative enterprise will just have to stay in the trenches and do without it, while the rest of us risk embarrassing mistakes and have a lot of fun." - Dan Dennett