While Tesla's Model 3 uses just a few electronic control units (ECUs), cars from peers use a complicated web of dozens of ECUs that are sourced from the parts supply chain. Relationships with the supply chain have been cultivated over the last couple of decades and traditional car makers are reluctant to sever these ties. Tesla on the other hand is not shackled to suppliers and has much greater control over its hardware. The electric car maker has tight control over its hardware and almost all key technologies in its cars, and can even perform "over the air" software updates to improve or enhance the functionality of its cars.
The real reason for holding off? Automakers worry that computers like Tesla's will render obsolete the parts supply chains they have cultivated over decades, the engineer said.
Such systems will drastically cut the number of electronic control units, or ECUs, in cars. For suppliers that depend on these components, and their employees, this is a matter of life and death.
So big automakers apparently feel obliged to continue using complicated webs of dozens of ECUs, while we only found a few in the Model 3. Put another way, the supply chains that have helped today's auto giants grow are now beginning to hamper their ability to innovate.