We can see why
Ford dealers wanted to keep this van in the lineup. It's very different from the Windstar. Like all the front-drive minivans, the Windstar is essentially a tall, roomy, front-drive station wagon, while the rear-drive Aerostar is more trucklike, with a stronger work ethic.
GM's Astro/Safari twins offer more power and higher load ratings, but the Aerostar is a little more modern and a little better looking. Both manufacturers offer all-wheel drive, and both offer plenty of comfort and convenience extras.
So the choice gets to be a matter of what's important to you. But isn't it nice that the choice still exists?