I've always loved that Draper pic, it's exactly how I squat with the wedge and all. But I've always wondered wtf is up with that bar??
Bar took a set from being left loaded on narrow uprights for too long. Most old equipment was very narrow, and when you'd leave a bar loaded for a few days, they'd take a bit of a set at the ends, then they'd usually get moved to the squatting area where the bend didn't matter as much, and it would get worse over time.
Most new equipment is built very wide now, so it's less of a problem.
Also, in powerlifting lifting gyms the bars were sometimes bent like that for comfort, as it allowed you to take a wider, lower grip that felt better for the shoulders, particularly with larger and taller men.
Here's a new version -
.