Strange, the military and industry have.plug in computers that slide right into a common backplane. An update is as simple as pulling the old one out and sliding the new one in, as long as you stick with the same bus architecture. The genius doesn't want to make updates easy, he wants you to buy a whole new vehicle. So much for sustainability.
Car sales are much more important to the company than you longs give it credit for so there is no way in hell Elon will ever put in updating computers - he wants you to buy a new tesla.