I find people useing the ratio number arguments a bit misleading. None of the gt games had the full console amounts when they launched plus after newer versions came out the ps2 still sold tens of millions but the game sales dried up more. How many more consoles will have sold in the year after gt5 releases? In 2? How many in 3? To assume that for it to sell more than 10 million would need a huge ratio misses the point that tens of millions of ps3s will sell after gt5 launches as well.
How many 360s were out when Halo 3 launched? A lot fewer than there were when it hit 11 million.