I’M SURE THIS WAS PROBABLY A RHETORICAL QUESTION BUT IMMA ANSWER IT. SORRY, NO RUDENESS IS MEANT.
Pink leader is a recent development (as in the original magical girls were not always pink), but it’s the same reason Barbie clothes are predominately pink. People in charge think little girls like pink.
Magical girls with non-pink main characters/”leaders”:
Pretear - dress sphere so she gets multiple outfits/colors
Sailor Moon - blue/magenta
Ultra Maniac - red (green, blue, pink accents)
Uta Kata - dress sphere so she gets multiple outfits/colors
Cardcaptor Sakura - multiple outfits/colors
Creamy Mami - purple/yellow
Ground Defense Mao-chan - Red/Green (pink hair tho)
Magical Emi - Purple/Blue/Yellow
Magic Knight Rayearth - Red
Fancy Lala - I think it’s blue? It’s been a while, I could be wrong with this one.
Minky Momo - Red/Blue (pink hair tho)
Day Break Illusion - Red/Orange
Fantasista Doll - main girl is red, and then the “main doll” is yellow.
Choujigen Game Neptune: The Animation - purple
Panty & Stocking - Red/Pink & Blue (one has pink in her hair, but it’s predominately purple)
Futari Wa Precure - Cure Black has pink accents but she transforms at the same exact time as Cure White who is white/blue
I’M SURE I COULD THINK OF MORE but that’s all I can come up with for now.