Because they are sh*t!!
I live in one of the worst hit areas and trying to get to work this morning and yesterday morning was a pain.
I have to go up a small hill just as I exit my drive and it was preety icy but all the neighbours cars were getting up fine, a host of other MKV diesels got up fine so I thought there would be no problem. First attempt got half-way and then it just got worse and worse!! The traction control just kept cutting the power so no matter how hard I pressed the pedal none of the ponies were being released. I tried all sorts of methods but evetually got up by travelling like a nut down my drive, drifting round my corner at the bottom and literally rolling up the hill.
I then got to the bottom of the road which goes quite steeply down hill. I pressed the brakes to slow down but nothing my car was sliding on ice towards standing traffic, I was adement I was going to crash. My car eventually ended up going sideways down the road missing parked cars by inches hurtling closer and closer to the traffic. How the hell I managed to stop and avoid rear ending my next door neighbours Range Rover I will never know. I literally stopped inches from his bumper. It was like something out of a movie
I then eventually got out of my junction to again go up a small hill. Again it was struggling to get up. I crawled up at 2mph with a queue of traffic behind me giving me grief. A guy in an R32 was on the opposite side of the road as I travelled up the hill. He wound his window down and shouted 'You should have got on of these, I have had no problems this morning'