I think it has to do with the fact that Mahler was primarily an artist consummate and an intellectual. I perceive that most of us here at the Gustav Mahler Board are of the same ilk. Bruckner was a spiritual man, to the extreme in the traditional sense (i.e., the Roman Catholic Church), and what flowed from his pen was guided by that spirituality. We may throw J.S. Bach in here, along with Bruckner, but Bach's spirituality was guided by what Sir Thomas Beecham called "Protestant counterpoint".
In his personal life, there was certainly more to have interest in as far as Mahler was concerned, and there are too many issues with him as to where to begin. At least, as far as success with the opposite sex was concerned, Mahler was more successful than Bruckner, to a limited degree. Thus the lack of acted-out drama with the opposite sex with Bruckner, and more so with Mahler. As an individual, Mahler knew what he wanted, and set out to try to achieve his desired goals. Bruckner didn't; thus that's why he was the continual revisionist of his works.
Wade