Why can i grow a stache but not a complete beard?!

Been 2 years now since i have my medium sized stache (French style, like it flip a bit both side naturally) and i need to trim it every god damn week so it doesn't look like a god damn panache (antlers), but i can't seem to manage to grow a god damn beard! There's always been missing spots and it's unequal. Im good with my stache i really love it but that is frustrating how does that work?!

Never used Minox but you guys seem to know how facial hairs work so i'm asking! Thanks!