Suz helped articulate my point a little better - thanks, Suz!
To go one step further, to my eye, because of the discomfort of all the extra fabric squished into the denim jacket arms/armpits/bust area, the look seems pretty contrived. I am on Team Effortless, and yanking on a fitted jacket over a bulky sweater seems anything but effortless - I even hate it when thin sweater sleeves bunch when I stick my arm in a blazer, so I can imagine all the pulling and contorting that would go into this look.
Still, I do like the proportions that you mentioned, as well as the fit-flare effect. Maybe this could be achieved with a fine-gauge sweater with fitted arms and a trapeeze or babydoll cut?