Tyler Cowen points out why certain things we study are obvious:
Things can be obvious if they are simple. If something complicated is obvious, such as anything that anybody seriously studies, then for it to be simple you must be abstracting it a lot. When people find such things obvious, what they often mean is that the abstraction is so clear and simple its implications are unarguable. This is answering the wrong question. Most of the reasons such conclusions might be false are hidden in what you abstracted away. The question is whether you have the right abstraction for reality, not whether the abstraction has the implications it seems to.