Rear axle setup. Most people who want the most interior space were buying suburban or expeditions anyway. The Sequioa lives in a sweet spot as the only real capable 7-seater off roader that is bigger than a 4Runner but smaller than a Tahoe and can still tow.
It’s the spiritual successor to the 1st gen Sequioa which sold a ton, the second gen (which was bigger and with independent rear) never really sold well and nearly got cancelled.
My biggest problem with the new one is price. We will have to see how many units they sell.