One thing that this article only touches on briefly is that more and more AWD systems today are just open differentials plus the TCS instead of using more expensive and heavier limited slip differentials. These modern systems are lighter and cheaper but they have disadvantages; not least of which is that using the brakes to force power to move around wastes torque, and it's only going to be as good as the sensors. If the ABS/TCS system has any issues your AWD goes out too.
I've owned cars with every type of AWD system (Audi, Subaru and currently a Honda) and day to day they all work just as well. Given that, I suppose the manufacturers are ultimately right to go with the cheaper and weight saving system.
The brake based system is great if the traction control is programmed for "get me up this snowbank" and not "prevent me from being an idiot"
There was an episode of Dirt Every Day where Fred and co. took a Jeep Renegade(?), or whichever the small one is, off-roading there were some great scenes of the traction control in action. Basically by spinning the dial to rocks the traction control knows to use ABS to approximate how one would work the brakes with a torsen.
The Honda VTM-4 system is quite good in it's intended operating environment - which is operation during winter weather. It uses electromagnetic clutches in the rear differential housing to direct torque to the rear wheels with left/right independence. This gives you the effect of a locking differential, up to the friction limit of the clutch material. There's no center differential in the system, and the front differential is open (but Honda includes a TCS, which is cheap because once you have the ABS sensors & pump, it's just software).
Even during good weather on dry roads, the system has benefits by engaging the clutches when accelerating from a stop, so all four wheels are driven when you need to get going. The clutches are disengaged after about 20 mph so you get the fuel economy of a FWD vehicle.
I've owned cars with every type of AWD system (Audi, Subaru and currently a Honda) and day to day they all work just as well. Given that, I suppose the manufacturers are ultimately right to go with the cheaper and weight saving system.