Glad to see someone bring this up. I've noticed this since the first one I was behind. Yesterday I saw a 18" base model, and I actually had to go under it with my tape measure. The rear a arm low point was 5.5" off the ground, and the rim was 6" off the ground.
This is illegal is most states, for obvious reasons you can't have anything hanging down on the driveline that is lower than the rim edges, as if you get a flat tire, or loose a tire, it will hit the ground. Its only a matter of time before there is a statement about this.
I completely shake my head when I saw a tahoe in front of me in me one lane, and a subaru next to it, and the subaru has literally twice the clearance.
Typical design by committee with zero common sense.