7" is only 'traditional' if you haven't been around bows longer than 4-5 years. Brace heights just came back UP to 7" fairly recently. Many used to be in the 5" range to squeeze out a little more IBO speed. Problem was those bows were so critical of shooting errors that most people couldn't shoot them worth a darn. So, low brace bows failed in the market place and manufacturers went back to making bows that were a little slower but reasonably easy to shoot well.

Not to mention that bows braced that low are practically impossible to shoot while wearing cold weather gear.