"...all mature with lots of existing designs to work from and knowledgeable people to poach."
Of course, but the devil is in the details. Yes, it gets a car built, but at what cost? Dr. Robertson has a background in maritime studies and extensive experience in automotive sales and marketing, along with purchasing. When he mentions that it will be "easier" for BMW, I have to think that he is referring to "financially easier".
Having all of the pieces is not good enough, because it does not ensure an optimal production line. Sooner or later, all of the above will (or could) have autonomous cars. The winners will be those who do so without pricing themselves out of the market. I have to agree with Dr. Robertson that BMW, (and Ford, Honda, etc.) can add autonomous driving to a commercially successful car more easily than tech companies can add optimized vehicle production lines. It will be much cheaper to add the tech than to add the entire production line. And, yes, the poaching will be critical, but works both ways.