It did. It just wasn't added to the series, I don't think. After the Shishio arc I lost track of where the series was going and all I knew is that it went to filler.

I thiiiink there was a huge arc focusing on Sanosuke, too, that wasn't in the series? Or was it and I'm getting my mediums mixed up? Gah, I have to go back to my manga copies and check.