Yes in practical terms this is very true, I've just been looking for an excuse to have a tinker trying to build my own as cheaply as possible. I think the thing is theres a certain satisfaction you get from doing something yourself even if it doesn't make economic sense, for example I bought a complete set of re-fretting tools including a gizmo to pre bend fret wire to the right radius all to be able to re-fret (one partially, one completely) two basses, probably cost me far more than paying someone to do it.