Just saying a bigger install base leads to more sales is not true, there are many other factors such as advertising and hype, both of which would be way more of GT6 was on the PS4. Using that logic for bigger market = bigger sales then that means that the PS2's top selling games would have destroyed the PS3's since it has double the install base. With the exception of GTA SA and Vice City the top software sales are pretty much identical. When the holiday season comes and people are on the fence about getting a X1 or PS4 and they see X1 with Halo 5 and no big system seller with the PS4 the average person will pick up a X1. The PS4 needs a big system seller to compete and it doesn't have to be an FPS to be competative.
So lets see... If you sell a game to 5 million people, how many can you get?
If you sell a game to 80 million people, won't that result in a potential for higher sales?
It isn't complex math. The bigger your user base, the higher your sales potential. That's all it is. I don't understand what you want to imply, but if things were as simple as you want them to be, then every single game would be released on the next gen.
Oh but here's a news flash for you. Game producers are smart, and instead of doing what you want them to do, they're doing the sensible thing: release stuff on X360 and PS3 because there are more users. Think about it. Are you smarter than they are? Then maybe you should own a major game studio and show all the others how wrong they are.
Pfft. Please don't argue anymore it's useless.