It really is a mind bogglingly stupid comparision ...
The XBox 360 + PS3 have almost 150 million install base between them
The 3DS has 22 million right now and maybe 35-40 million at best by year end
GTAV launches in spring, giving it a good 8 months to sell this year on top of that
Pokemon X/Y launches in October giving it 2 1/2 months most likely at best to sell
No sh*t GTA should sell better, nothing ground breaking about that prediction.