I used to blame height for my depth until I lifted with VTBalla who is 6'5" and outsquatted me by 200lbs with room to spare on his depth.
Play with foot width and positioning. For me I have a much easier time hitting depth having moved my feet in just slightly wider than shoulder width, and have a very minor toe flare.
As Jim Wendler wrote in a recent article, the key to hitting depth with this setup as a raw squatter is to break at the knees and hips simultaneously. I used to try to have my knees not shoot forward even one millimeter, now I let them come out close to my toes (hard to do with a wider stance if you have tight hip flexors like me). The key is to make sure you are still sitting backwards as your knees shoot out. There should be both sitting back AND knees forward (just a bit)... only doing one or the other will make it hard to squat with long levers.
Here's a vid of the first time I hit 365. Obviously it's not perfect form since it's a max, but notice how by the time I get to the bottom, 1) my knees are over my toes, 2) my ass has gone from 6" in front of the frame to being partially obscured by it at the bottom.
Edit: yes it's debatable whether I hit depth here, but I got three whites with 374lbs at a meet not long after this.