I'll keep it short since I'm tired and it's very late here.ITNW was great, but it didn't quite make them any close to what they are now.
January 2009, the release of gee and rising in popularity.
Gee was the bom.
February 2009, WG having their world tour, lasted till March.
June 2009, they released an english version of nobody. And the release of genie.
The absence of the WG may have been a contribution, but sooner or later, snsd was doomed to get into #1.
Why? Because what I believe was the MAIN factor is SNSD's own enthusiasm and skills.
All the girls shined at their area.
5 lead/main vocals were awesome, their appearances at many different shows captured everyone's attention.
Yoona, no need to mention how Korea is all over her, she is more loved/ popular than Sohee ever has/will be.
Yuri overshadowed her senior son dam bi when she performed with her.
NOT to mention their great variety skills, snsd are great entertainers. We all can agree WG lack in that department.
So, for me gee was the bom (it was more hit than nobody I believe), genie maintained their success, WG's absence might have contributed, but not that much, it was going to happen soon or later.
Your thoughts?