That is not always true. What ALWAYS works is moving the main gear a minimum of 1 inch forward (towards the nose) of the center of gravity. The gear can often be moved farther forward to better ground handling.

I've been building for over 30 years, and this hasn't failed yet. If you look aroud a bit, you will find many planes with the main gera out of alignment with the leading edge of the wing. By the way, which leading edge should the gear align with on a biplane? Or Triplane? How about a Canard? See what I mean.