I've stopped playing many other otherwise great games that I was happy to pay for when this kind of economic model was introduced. Something I loved being destroyed by greed.
The more I think about this, the more upset I am. In my opinion this just kills the original Angry Birds UNLESS they follow recommendations like the one made by Since the power-ups have already been released it is unlikely they can make the change. Completely invalidates the leader boards and what made AB so much fun.
With the power-ups added people can either spend their way or hack their way to high-scores. This implementation was clearly done to increase the revenue generation potential of the game, however it creates an uneven playing field and saps the motivation to play.