delta drag
The area will remain constant if the math is done correctly. A 10 inch chord wing with a 1 inch thickness and a span of 40 inches has 40 square inches of frontal area. Let's now increase the aspect ratio 4 times by keeping the same wing area. An 80 inch wingspan with a 5 inch chord length. The thickness is now half an inch and the frontal area is still 40 square inches. It also works for tapered wings.
If the wing area is decreased and loading increased (as mentioned in the article) then the frontal area will decrease.
If you change airfoils then the frontal area will change given the same area. The article you are referring to is badly written. He could have used the same aspect ratio in his example and the point would have been the same. If you read closely and understand it he is talking more about smaller wing areas than aspect ratios.
I have personally witnessed a high AR glider at over 260 mph. I know it is another bad example. It was out of a dive. It just goes to show that high AR wings can have low drag.