If I were you, I would say "Diligence at work(or Diligent work) may lead to a decent life." Notice that "lead to a decent life" is different from "(someone) lead(s) a decent life" in both meaning and structure. And remember, still another problem remains: I'm doubtful whether native speakers of English identify with your notion and whether they put it this way. Grammatically correct sentences may not be correct, as native speakers may not speak that way. So, in my opinion, we should put more effort into our job of learning English to learn to use English their way, or at least to get closer.