This design was done for a car with narrow tires and higher tire pressures. I believe the lower tire pressures and bigger tires we run on these cars puts a lot more twisting moment/torque on this device which will over time fatigue it and it will fail.
Maybe, but I feel like we give manufacturers and factories a lot more credit than we should.
My son had an engineering job in undercarriage at Caterpillar Tractor Company for a couple of years in "HEX" (hydraulic excavators). The hydraulic excavator market has a lot of competition, and is somewhat price conscious. Now, Cat has been in business for a long, long time, and long ago knew how to make tracks last for many, many years… but it's expensive to be the best, and being the best doesn’t always translate into making the most money.
What Cat doesn't know is how much they can cheapen things up before they fail "prematurely" (within the warranty), which is what Wall Street and the analysts are looking for. My son had the job of looking for places to cut before they cut too much.
This was not done in a lab, it was done in the field. Big operators would get track for a discounted rate, and run it until it broke. Mike went around the country looking at broken or worn track, and around the world looking for some 3rd world hell-hole where they'd make a shoe or pin $2 cheaper than some other 3rd world hell-hole. The job was a stepping stone, but as you can imagine -- he didn't like it very much.
On the other end of the spectrum -- Tesla is (apparently) developing their miracle self-driving "autopilot" software by throwing it out there, and seeing how many people die to determine how they might make it better (or not).
"Your wife and only child plowed into an overturned semi? Sorry about that -- but you gotta break a few eggs to make an omelette. And look -- we made some programming changes to a couple lines of code, so their lives were not cut short for nothing. Our stock price went up 2% today."
Which brings us to the crush cage in question. I'm not sure, or even confident, or even persuaded that VW did much beyond design a cage that looked like it ought to crush and probably wouldn't tear within a time-frame they thought was responsible. Remember -- this was a time when we all took a lot more risk. People rode in the back of pickups, nobody wore seatbelts, everybody rode bikes without helmets, and kids roller-skated without being padded up like an NFL running back. If those Sainted Germans did any testing at all, it was to determine the cage would actually crush, since that was the primary objective. Nobody was designing this to last 70 years.
We get the picture of serious looking German guys with clipboards, scowling and wearing lab coats, with a mechanized gizmo twisting back and forth and back and forth on a crush-cage. We see the Sainted German Engineers feverishly writing something down (their lunch order perhaps?), and talking about getting better (Swedish?) steel, and alloying it with nickel mined from Mt. Doom, and heat-treating with tears of a unicorn.
I'd bet $100 the guy in charge drew the crush cage up and said, "that oughta' do it" and sent it to pre-production to make sure it would indeed crush in the event of a head-on. It did, and the steering column no longer impaled the driver, so off it went to production.
And here we are.