#1 They are too good to be in a makeshift tag team
Looking back at the booking of the WWE Championship in 2018, Rusev and Shinsuke Nakamura were both in prominent positions where they could have won SmackDown Live’s top title from AJ Styles.
Rusev’s only title opportunity came at Extreme Rules, where Aiden English inadvertently cost him from getting the victory, while there would have been very few complaints if he won the title earlier in the year during the height of the “Rusev Day” phenomenon.
Nakamura, in contrast, faced Styles in four consecutive PPV matches (WrestleMania 34, Greatest Royal Rumble, Backlash and Money In The Bank). It appeared as though the natural conclusion of the storyline would be for the Japanese star to become WWE champion, but “The Phenomenal One” retained on every occasion.
Simply put, whether they are challenging for the WWE title or not, the duo are too good at being singles competitors and too important to the men’s division to be involved in a makeshift tag team.