I think you can make a case for Mr. Bates being the main character of the story, but I would still argue that Mrs. Bates is the true principal character.
You say that the story is built around Mr. Bates's attitude but I think that it is built around Mrs. Bates's feelings towards her husband. We see these feelings revealed through her talking about his absence.
To me, the story is about how dissatisfied Mrs. Bates has been with her husband. She feels that she has married beneath her and is impatient with him because of that. At the end of the story, she comes to realize that the problems in their marriage were her fault.
So Mr. Bates is central to the story, but only (in my opinion) as an object for Mrs. Bates's thoughts and feelings.
If you compare the storys plot and characters with that of D.H. Lawrence you will find that there are alot of similarities between them. Mr. Bates is in fact Lawrences father and as his father was like a shadow in his house the same way Mr. Bates is also a shadow in the storyline. However Mrs. Bates and Lawrences mother have the same character to play i.e. his mother was dissatisfied with her husbands work so is Mrs. Bates. I argued once that there was alot of dark glamour which was depressing for many readers and students taking the subject in class and my professor said that Lawrence was actually born in the 18th century that was the age of industrial revolution of cant see and cant see. He therefore put his opinions or rather told them in the forms of short stories and novels.
Its quite evident from D.H. Lawrences life that this was just a small picture of what he saw of the world in his time and Mr. Bates fits the role of his father perfectly. In my opinion Mr. Bate did carry on the storyline as he was one of the supporting characters of Odour Of Chrysanthemums but it was Mrs. Bates that lead the story.