Why is DirectFB not more widely used in GNU/Linux? Are there crippling limitations to it that don't exist in X11?

Question

As far as I understand, DirectFB offers hardware acceleration for many kinds of graphics cards. Additionally, it\'s smaller, faster, and uses up less memory than X11. Why then,

Answer 1

Simple, because DirectFB doesn't solve any problem. For embedded systems it's fine, but for desktop, you lose a lot and don't gain really anything.