This has been my current deliberation: If the characters were special, and as a writer, you've managed to create a bond between reader and character, would not whatever conflict they find themselves carry the story? I read Hemingway's The Sun Also Rises, and really not much happens that is not beyond the realm of our realities (or the realities that movies, television, drama, books have created). However, because the characters were special, and sometimes we didn't understand their motives, we were drawn; their common problems and dilemmas became as large as life, and I was hooked. So I suppose, after reading that book, I came to the realization that events need good characters, but good characters don't need incredible events.
I find I'm surprised I agree with you here. Reading your post I began to think back over some examples of stories I like which are more of the esoteric variety, less mass appeal with each its own little cult following. (I won't cite examples, ) But as I think over these specific stories, it dawns on me that it's not the plot I like but the feel of the personalities themselves. The catch is, I think, is that the niche audience thing is unpredictable and commercial success from it is usually found by accident.