How do you determine if you don't have interest in research or merely don't have the discipline?
First of all, you completed a Ph.D. in mathematics-- I would hardly call that a "lack of success."

Secondly, I'm a big advocate for getting paid to do what you're good at.  And from an economic point of view, that's the best thing you can do for society.  If you want to tinker with math problems in your spare time or build up self-discipline and concentration skills, by all means, go for it.  Such things will sharpen your skills in every aspect of life.  But humans are pretty straightforward creatures: we tend to pursue and get better at what we're interested in, and we flounder when put in career paths that just don't match our personalities.  You're not a lazy or unintelligent person for not wanting to do math research.  You already tried the path when getting your Ph.D.  If it didn't fulfill you then, it's definitely not going to if you try to force yourself back into it.