Earlier quoted context omitted.
I maintain that if you know what you're doing, advertising is ridiculously profitable. Most of the time though, most startups that use advertising do it because: they don't have other business models, and so advertising is shoe-horned in. On the other hand, a startup that knows what they're doing will know that building out the correct audience is the way to go - if you provide your clients (the advertiser) what they…
Any examples to support your case?
Google isn't a startup anymore. If I were to be asked about more recent startups, I'd list Buzzfeed, the 9gag peoples, Ben Huh's company (can't remember the name) amongst those with quite decent strategies for advertising. You may notice that they're almost all content based companies/startups - that's because it's easier to build audiences with content.