Illmatic impacted rap enough to shift the dominance of the west coast back to the east.
The East was not dominant after Illmatic. Warren G's Regulate was a bigger deal than anything coming off of the East until Ready To Die. I mean, even when Outkast popped off in 1994, "Player's Ball" and "Southernplayalistic" are G Funk records sonically. Biggie's "Big Poppa" has a West Coast swing to it too.