OK, what's the point

I'm stumped on level 466, so for the first time I looked up the walkthrough. I watched it, and was stunned that that in the walkthrough, the birds were level 8. I'm level 34/35, and get just as many extra cards by scoring 2 mil per level as the walkthrough example get for 100K.So, everything I've done to upgrade my birds is worthless? The levels increase in difficulty as my bird level increases? WTF? I no longer see a point to the game.