It's not easy getting links. More importantly, if you have a great product where everyone else has great products, the marginal benefit of having the best product with the most amount of authoritative links is huge, because the # of clicks that come from the top result over #2 is monumental. So even if you get thousands upon thousands of links, like those that rank for "cheap flights", it's the site that gets thousands and thousands +1 that will win the day, and make millions more on a long enough timeline.
