Naruto is Hokage because that completes his arc. Something Sakura never had.Sakura wasn't the average student you are really trying her
Sakura= super smart, super skillful, high mental prowess ( best at genjutsu, she skill in part 1 was compared to that of a jonin), perfect chakra control, no stamina
Naruto= super stupid, high stamina
Sasuke= some of both
Naruto is hokage by plot, Sakura is the one who would be the hokage based on skill and intellect
Sakura is a mother , not a housewife, she isn't relying on some man to support her and her child , Hinata is a housewife, and Sasuke said that Sakura isn't some weak woman so she is just as capable as naruto or Sasuke
Sasuke is only an agent because he is the only one capable
Remember this quote?
"To Become Hokage one must master patience, training, discipline. But above all one must possess unearthly talent. Only a few have been bestowed this title through the ages. Through training comes mastery. Through mastery comes victory."
Sakura can only stand next to Naruto and Sasuke, because she's a member of Team 7. Not because she possesses any special traits, fight record or interesting backstory.