>>87798003It's less about being balanced and more about knowing how this thing usually goes and eliminating obvious dead ends. Ignoring Star's romantic interests for a moment, Marco's got a typical 3 way harem decision tree. He's got The Opposite Sex Best Friend, The Crush, and The Stalker.
The Best Friend branch has the most weight at the start purely from genre convention. The Crush branch usually doesn't go anywhere, but it's being vindicated in recent episodes so it's putting on the pounds as well. The Stalker is just your typical Helga Pataki. For whatever reason, that's also viable (because of those weird genre conventions).
Star has the same archetypes in her tree but two of them are more obviously nonstarters. Her Crush is barely sapient so no one expects him to be endgame, and her Stalker has made more headway in rekindling a relationship with MARCO than with Star. A male stalker isn't nearly as viable as a female one for whatever reason, but anyway all but The Best Friend branch on her tree are either stunted or already withered. The Marco branch is the only one that's growing, and being the only option left on Star's tree basically preempts anything going on in Marco's.
I've watched too much television.