Definitely a good explanation. The scary thing is my principles of communication course last quarter spent a lot of time on quadrature modulation, and taught me less about it in that time then that youtube video did in under 20 minutes!
The RCA method of building a chroma reference oscillator with feedback to correct phase errors (ie a PLL) was a gross over complication of achieving recovery of the burst reference carrier along with a color killer to switch off the color CKTs when the burst was not present...I like GE's method better: dump all that, and feed the burst to an RC tank circuit that will keep ringing until the next burst comes and use a limiter stage after it to keep the amplitude constant....It was like using the burst to strike a tuning fork, sitting back and listening to the tone.
If you want to see genius simplicity Admiral made a single tube high level demodulator shown and discussed on pg 127 of the third edition of Buchsbaum's Color TV Servicing...Only lower tube count color stage I can think of is someone on here mentioning some self-oscilating high level demodulator.