These crushed heels occur in feet when the hoof wall and the bars are relatively weak. If the bars are taken out too much, there is even less support for the heel so it would collapse more.
I'm inclined to disagree with you here John - I think the weak lateral cartilages AND digital cushion are the origin of the problem. I think that poor hoof mechanics (and racing/jumping are so hard on the mechanics of the heel region of the front feet that they are a major risk factor IMO) creates the weak/thin walled foot in the first place, and then the thin-walled foot just isn't sufficient to hold the horse up so it folds under.
