Why have keel preferences changed for cruising boats?

[Emoyeni]

I was wondering if anyone out there knows why there has been such dramatic and industry wide shift away from fuller keels with more comfortable but narrow hull shapes in the pre 1980's to the fast, voluminous, but pounding shape of modern boats. I mean it's not like the cruising destinations are different. It's not like sailing is any different. And it's not like people can't afford to buy one kind or the other (even though bolt on has become more economical - people are still spending 2 million dollars on a new Amel 60, for example). So why has the shift been so complete and virtually unanimous?