I can think of many reasons.
1. Frank Layden stepping down, and Sloan (including his hard-nosed reputation) being in the right place at the right time.
2. Stockton & Malone being self-motivated and probably wildly successful no matter the coach under whom they had played.
3. An owner (may he rest in peace) who was content with--and loyal to--letting ol' Jer accomplish above-average performance (Who says I don't give Sloan props?

), even when the team had the potential to do better and despite never garnering even one ring (the Jordan excuse goes only so far, and he didn't play in the league for 20 years). 41-41 seasons were the exception, not the rule.
4. An owner's son continuing the owner's legacy, including a tolerance--conscious or unconscious--of Sloan's disenfranchisement & underdevelopment of role players who could help the team. To Sloan's credit (Wow! Another compliment coming!), JS is more subtle about his inequitable and suboptimal treatment of players (based on performance) than he was in years past.
5. Your mom.