Sure, nothing is stopping any decent company from making a IP as popular as GT. They just need to make the right type of game (mass market), and market it the right way.
Heck, Nintendo just created the Wii Sports franchise that is a +10m seller (Wii Sports Resort over 10m, Wii Sports sold 3.7m in Japan, and probably would have sold 10m WW if it wasn't bundled). Activision has the Modern Warfare franchise, which sells 18m combined. Even the Guitar Hero series broke 13m sales with the 3rd version. And all of those games are relatively new.
The real question is when will Sony acheive that type of success again.