Brian's "business" feel is something you can't learn from videos, scientific verbal explanations, or rushing to the range and trying harder with trial and error and error and error.... and then declaring 'I got it'...!!! You got nothing and your only deluding yourself.
What Brian is doing is imposing body rotations by manipulating you with his hands, etc.. IOW, he's force-feeding you to rotate your body in a proper kinetic sequence and posture. He's virtually programming you into a golfswing.
It's like robotics, where the robot arms are physically pulled through it's operations for the first time and the movements are tracked by the robot computer program and stored. How did you think robots learned to operate repetitively on a production line?!
The power emanates from your hips to your shoulders provided you time it properly for your arms and club... and then your arms are finally pulled through and flung out... the lead arm doing nearly no 'work' and the rear arm extending with correct timing while the club just follows.
Of course this assumes you are fit to swing, rotate, thrust, jump, balance, aim. The challenge for most is the timing and whether you can transmit the lower body power to your shoulders through your core. Most can't do it because the core is compromised and weak... and the sequencing is inconsistent and screwed up.
If you watch demo videos, many of those swinging do not have an X-Factor stretch and the hips and shoulders rotate in unison. It's okay for wedges, but it produces a powerless drive.
I bet Brian can even help even the most decrepit by just laying his hands on them.. and then eureka.. they're cured ...!!!!
I will be better for it 