Peltzman's 1989 retrospective on the economic theory of regulation after a decade of deregulation showed that his model held up reasonably well. The kinds of cost and industry structure factors he expected would affect the viability of cartel-enforcing regulation did affect changes in regulation over the period, on the whole.
I have no explanation for this. Story at National Post mildly NSFW.
It can be hard to explain the pattern of regulation.