#3 RAW is a sports entertainment driven brand

Lest you forget because of the quality of wrestling, NXT is actually WWE's developmental brand.
While some amazing independent stars like Adam Cole and Ricochet are setting new standards for the business, Lars Sullivan is comparatively new to sports entertainment. When he gets called up, he may need storylines to get him over. RAW's the brand for this.
SmackDown Live, while still based on sports entertainment, often relies on in-ring action over storylines.
You don't see Rollins chasing Ambrose for the entirety of the show backstage or Braun Strowman takes security guards out, once again in the backstage area. In a lot of ways, SmackDown Live is more similar to NXT than RAW.
Sullivan has grown by leaps and bounds. But he may flourish more in an entertainment-driven show, rather than in SmackDown Live.
Strowman became a great performer over time and there's no reason why Lars Sullivan can't do the same.
Did a WWE Hall of Famer predict John Cena's heelish ways long ago? More details HERE.