Based on apple history, they focus on battery life and form factors more than power. Average users do not need quad core, but they want more battery life.
Unfortunately, apple cannot make laptops based on small number of users who want to run latest 3D games and intense applications.
Exactly, the releases due in 2011/2012
they will feature ivy bridge processors, in which even the entry level chip will be 22nm and feature 4 cores. the desktop version will feature up to 16 cores on a single die. (hence I don't get the fuss about Sandy Bridge!)
Wikipedia said:
Ivy Bridge processors may be released as early as the second half of 2011. Ivy Bridge will replace dual-core processors with quad-core processors at the entry level segment, while delivering eight-core and sixteen-core processors for mainstream and higher-end level segments.