I´m not sure how it is in the US but as I see it, in Europe we have three different types of airlines.
1. Low cost no service airlines. For example Ryanair and Easyjet (Southwest in the US?). If you fly with them you pay extra for everything. For example you pay to check in bags, water, to board among the first (even if you travel with children) etc. The tickets are sometimes free so we are then talking LOW cost but the tickets can also cost much and you still have to pay to get some water on the plane.
2. Normal cost almost no service airlines. For example SAS and KLM. Most of those airlines are airlines that have existed for a long time but now they have problems and try to be more like the low cost airlines to earn money. SAS don´t offer food or drinks (unless you pay for it of course) on European flights anymore and the overall service has gone down but so has the prices too. (I guess that both AA and United are in this category if we look at the US)
3. Airlines which still offer the service they used to offer. British Airways is the only airlines I know in this category. They still serve food (on short flights, for example London-Stockholm, it´s sandwiches so it´s not much but at least it´s something to eat) and drinks and the overall service is still good.
The prices on SAS and BA are often almost the same so SAS should earn more money but they don´t! SAS loose a lots of money and BA earns a lots of money so extra charges can´t be the solution!!!!
The real low cost airlines earn money and the traditional airlines earn money so the problem is the airlines that try to be like low cost airlines, for example AA!
Charge extra for everything and you loose your customers!!! I will never fly with SAS as long as British Airways still keep their service!