CPA vs Amazon, which is profitable?

I own several CPA game sites, I can say earnings is cool since I can easily scale up by grabbing more niches. But I don't know how long they will last. For amazon, most keywords I see are less than 2k search, which I doubt will make $1k/month.
So, its your turn. Which one is profitable?
Please don't reply base on what you read. I need practical answer. Others might know the right path to follow based on your reply.