Do you fly primarily in the US? Because I have noticed that most US airlines seem to be in a race to the bottom, but this is not the trend worldwide. I fly both Lufthansa and Turkish relatively frequently and everything about the experience with them, from the airports, to the customer service, to the food, is head-and-shoulders above every major US airline.
An even easier step would be Kayak allowing you to select how many checked bags you'll have, and baking those fees into the price. Less subjective than customer rating, but they still dont take even this minor step.
Enough passengers to fill every Jet Blue flight, apparently. The existence of airlines that are not awful budget ones proves that plenty of consumers are willing to pay more for quality.
It depends on how expensive. Airlines that lose my luggage, charge crazy fees and have incredibly narrow seats often get dismissed out of hand unless they have significant discounts. I usually just check southwest first because of this.