That's a true statement, and in fact the most likely time to get stuck is when turning around.
That being said, unless you're just going in circles, the vast majority of your driving is in a somewhat straight line.
When towing in the sand I always look for a firmer section of sand to make my turns, as that's the most likely point to bury the truck.
I've driven most of the driveable beaches ( and some not so driveable) from Washington to California, in both a SRW and DRW, hauling truck campers and toyhaulers. As stated sand conditions have a lot to do with what you can and can't drive on the beach. Common sense and the ability to air down will get you through most situations regardless of how many tires are on your truck.