In the long run OR On the long run (See more…)

‘In the long run’ is a better choice. The idiom means over a period of time, eventually, or ultimately. It is often used to describe the potential consequences or outcomes of a decision or action. 

The mix-up between ‘in the long run’ and ‘on the long run’ might stem from language variation or interference from other phrases. Language users may modify expressions based on their local dialects. ‘On the long run’ could be a variation that emerges from these interactions.