To be fair, GT4 released with a userbase of 80 million Ps2s. This is roughly 2 and a half year after GT3 released. Is there any chance that GT3 would continue to sell now? No, I really doubt that. So, the fact that the Ps2 userbase eventually reached 120M is irrelevant.
By the time its first year of sales was over, the Ps2 was only at 30M. So essentially, I'd believe that at least 1/3 (5M) of GT3s sales were actually on a 15-30M userbase. Now, I'm not saying that GT5 will repeat GT3's success to the same extent (far from it), but the argument that the Ps2 had a far larger userbase is actually rather flawed here, as it didn't.
When I write Fact: in one part of the post, and opinion: (or a similar word), it's not because I can then say "my opinion can't be wrong". It is to inform what part is pure facts, and which part I try to draw a conclusion in.
