And you are exactly right, that's how it works but the first step is getting traffic to your site and you have to do something stellar to attract enough people to make them even want to invest in PPC. No purpose of having a PPC if no one is using your search engine.
So yes, I understand what you want to do, my concern is that building up enough traffic to spark interest is going to be the challenge. Not saying you can't do it, just saying it's a big hairy monster.
More traffic definitely means a greater chance of earning more because there are people with traffic and still not making much simply because they don't monetize effectively. That's when it comes back to knowing WHO your audience is and defining this niche before you begin your site.