How Common Are Homegrown Linux Distributions?

Andreas Krennmair asks: "I'm planning to build my new Linux system from scratch, similar to Linux From Scratch. I'm currently collecting all source packages, and I wonder how common it still is to use a self-built Linux system, although graphical (or pseudo-graphical, curses-based) installation programs with automatic hardware component detection and great software package management systems are used in almost every modern Linux distribution. And are there any people left who still use Jurix or Yggdrasil?"