Why are princesses seen as cooler than queens?

Princesses are straight. Because of all the virginity.
Queens are queer - 'cause of all the sex.

Princess: Young, rich, mega privilege, no adult responsibilities.

Queen: Most of them are queen by marriage (political marriages are not for love, romance, or even if you personally like your husband). They have to always behave in public, be dignified all the time, responsible to their subjects, be nice and polite when they would rather not, in case they start a war, etc. Crushing responsibilities and expectations from your subjects. Read up on the late Queen Elizabeth 2 and her life. I wouldn't have wanted her life.

Thank you for your deep and detailed response. Have a nice day.

Disney

I was hoping for a deeper answer than that.

Sorry, but Disney princesses are the only explanation I can think of