@Curiosity – Tanc Sade (who plays the wild Aussie, Finn, amongst the Life and Death Brigade) actually explained it relatively well in an interview on Studio10 last week.
They were strong leading female roles at a time, 2001, when very few strong women were on television (that were the opposite of Paris Hilton or Jessica Simpson who ruled the screen at the time). The coffee drinking, fast talking, small-town humour were just the fun added to the mix, that meant even men watched the show without complaint.
Consider that when they made the recently released Gilmore Girls Funko Pops, they only made they leading ladies: Lorelai, Rory and Sookie. Not even the always present Luke warranted his own.
And just because it’s Tanc, sharing is caring… https://www.youtube.com/watch?v=Yea3DMovB4U