An article like this needs to at least mention that the relatively unsophisticated pricing approach by Southwest has led it to generally outperform the rest of its competition for decades (I know, staying out of bankruptcy is not a very high bar).
Since their fares are not comparable since they don't let anyone show theirs in the same list as other airlines, you really cannot know if they are cheaper or not. In reality this means they are able to set their prices on average higher than those who have to compete in a list. Better control vs. more exposure.
Much of Southwest's profitability actually comes from doing a great job hedging against fuel cost changes, rather than making extraordinary margins on the seats.
