as i said, it's a crude drawing...... the generator could even be delta wired too (Tesla'a patent has it wired wye), but the distribution point and the transmission system was basically what i was getting at. the secondary of the distribution point doen't necessarily have to be a wye with a ground either, as each of the 3 windings could feed the primary of a split-single phase transformer, where the secondary of the split phase has a center tap which is the neutral for two 120V sections which are 180 degrees out of phase, giving 120V for each half, and 240V total between the hots. this is the standard house service.
3 phase service (for large offices and light to heavy industrial) takes the points of the wye (or star) as the 3 phases, and the center tap as neutral. there's 120V between each phase and neutral, and 208V between phases. the neutral is grounded at one place, at the "service entrance", there are special applications that use 3 phase delta transmission directly to the end user, one of which is the motors for driving pumps for sprinkler systems in high rise buildings (obviously this isn't at the normal voltages in the tens and hundreds of thousands of volts, but at the 480V that is used for the motors).