How hard could it be to produce excellent work in the humanities? After all, we just make it all up anyway, right? It's not brain surgery, it's not rocket science. Not the really hard stuff.
Here's the thing, though. It is pretty difficult. You have to have half-way decent erudition, the ability to write and organize your thoughts. You have to not only know things, but able to make a case for your particular way of framing what you know. With canonical material, you have to convince others that you have something new to say, but with non-canonical material you have to make a case for why the material is even worth studying. Someone deeply involved in a field of inquiry, trying to do work at the highest level, is performing 'brain surgery" or at least "mind surgery," trying to alter the minds of others.
The people you have to convince are people at least as smart as yourself: the best people in your field. They can be extraordinarily tough to convince.