When you have the capacity to design CPUs, you can do a lot more. They likely hired him for his deep HW engineering expertise, which the article suggests. I doubt they are interested in making a CPU.
This strikes me as true. I suspect that one of the greatest challenges in creating self-driving cars is not the learning/training problem, but rather the problem of ensuring functioning sensors at all times -- which is where his hardware engineering expertise comes in.
I'm sure Tesla has little to no understanding of what they need or how to improve their product. They're probably just throwing darts in the dark, HOPING something works.
What makes you sure of this? Does something in their execution thus far indicate "little to no understanding of what they need or how to improve their product"? To me it seems quite the opposite, so I'm curious what you are seeing.
He was almost certainly being sarcastic.
The problem with Tesla's "autopilot" is that it works great, until it doesn't.[1] Its lane following is very dependent on lane markings. Bad things happen when the lane markings are insufficient to indicate where to go. Musk's rant: "We really need better lane markings in California."[2] This is not a CPU architecture problem.