It's true but because they control the majority of online ads end-users are stuck accepting their rates and agreements. I'm not saying that Google is bad but I don't really know how large a percentage I get from their ads. If there were more ad startups with a larger percentage end-users would see a better competition on percentage paid.

If startups are going to compete with big companies, they need to do it on innovation, not price. Big companies have the upper hand on price because they have economics of scale.

hmm, but the Big Four are like advertiser aggregators (probably a real term for that, reselllers?) since they resell the advertising. So this doesn't seem that surprising to me, the people it affects are other people providing a similar service as a startup. Or am I missing the point?