I’m pretty sure it’s because less people use it. They make fun of Gentoo taking longer to compile stuff on install/update, but that’s pretty fast nowadays. What really takes up time is making all the choices. I remember hours of selecting obscure kernel options and choosing use flags “what is ncurses? Do i need ncurses? What is sdl? Do i need sdl? …” I mostly use Ubuntu now, because I got no more time for that.