You've hit the nail on the head. I've been saying for a while that people are not attracted to JetBlue solely because of its fares. There IS more to choosing an airline than price. It's becoming evident that, on some routes, JetBlue's fares are actually higher on average than the competition, and I'm not surprised. I have not met anyone who has flown JetBlue who would not fly them again--in fact, the response is almost uniformly "I wish they flew everywhere!" And I'm not just talking about one or two people--as a New Yorker, virtually everyone I know has flown JetBlue by now. Mention any of the majors, by contrast, and the conversation automatically turns into a contest to see who has the best "bad experience" story. You know what I'm talking about.
I don't think JetBlue is immune from competition. Sooner or later, someone--besides Southwest, which has known this for decades--will realize that winning passengers takes more than low fares. Maybe the management at Song, for example, will finally catch on, and maybe they'll give JetBlue a run for its money. But even if they do, I am confident that JetBlue--as long as they can maintain the same customer-driven attitude--will do just fine.