I would dispute that. My impression is that they are mostly found on industrial and some trucks. Ford/GM/Chrysler certainly did not use them, or not much. The "usual" Toyota/ Denso alternator is not "one wire."
Again, for me one big downer is that they require a HUGE oversize charge wire to properly provide well regulated voltage at the battery end. This is even more critical in a trunk mount situation. Frankly, I see NO ADVANTAGE at all to a "one wire" vs any setup with a separate "sense" wire which adds "voltage accuracy" to the installation.
I do see the attraction (simplicity) and in fact have one on my old (6v-12V) Farmall.
