The drivetrain didn't, the concept of the car did. The whole idea of a rwd convertible 2 seater sports car was virtually gone. It brought back the open-top roadster. The Boxster, BMW Z's, S2K, and Solstice/Sky might not exist if the Miata hadn't revived that market.
Plus its had its impact on the motorsports world... when it came out the Miata was a cheap and competitive car. Meaning the people who can't afford other cars can still compete with them.