To a certain extent all of the airlines have multiple coach fare types, United is the most complicated in my opinion. In the world where research is easy to do it doesn’t take much effort to figure out what is what it is pretty clear on the United site and you can Google to get a simple break down. The airlines like all companies now have tons and tons of data and far more sophisticated IT which allows them to sell many more flavors than they once did. This simply is the way of the world these days in every industry. Believe me a ton of research and data goes into airline pricing and options both on the business profitability side and consumer acceptance side