This is an example of how google uses more than just keyword seo and backlinks to determine a sites relevancy. You've just identified two more factors that google uses for indexing a site; age of the domain, and number of visitors. It also takes into account the bounce rate as well.
There isn't much you can do to simulate that. Other than starting a site by purchasing an aged domain, your stuck with having a newer domain. There isn't much you can do to simulate traffic. You could purchase traffic, but it's not going to help much. You actually need traffic that's sent from google, so you just have to build it up. The only factor you can control of these factors is the bounce rate. The only way to keep your bounce rate down is to have a high quality interesting site that visitors will stay on for longer than a few seconds. That's not always easy to do.
So basically you've identified a few things that you can't control, but it's important to know about them to understand why many sites are outranking yours. The only thing you can do if you don't equal them in that area, is to do better in the areas you can do something about. Which is basic SEO and a good backlinking strategy.
