In my experience it's gradually gotten worse over time. Up until someone in 2010 charging people $1-3 up front worked well for me. Then sometime in 2010 it slowly stopped working as more of the 'top' apps switched to a free with IAP model. Consumers didn't want to pay up front for an app from an unknown developer when people like EA were giving their apps away for nothing.
In Europe, 2010 is when people lost their jobs because of the 2008 crash. I bet people like EA switched to IAP because they felt it was a way to bypass the newly-developed austerity mindset.
