I really dont think these two things are the same. Tesla has actual competition for EVs, mostly from BYD and other Chinese companies, but also MG and Nissan, even VW to some extent. The reason is that people have wildly different tastes and needs for cars, and some people HATE the cybertruck and hate touchscreens, and thus rival companies can make 'good enough' EVs and still sell them despite Tesla existing.
But IF Tesla is right and autonomy can only be solved by huge NN training, then NOBODY on earth has the resources to compete. You need a bare minimum of 2 million internet-connected cars with multiple cameras in customers hands, all over the world, for years, a huge datacenter, world-class AI engineering talent and at a bare minimum 10 billion available to buy nvidia chips, if they will even sell them to you.
No amount of money makes that list of requirements appear overnight. I think even if a nation-state declared it an essential national project and went all-in on trying to generate a competing setup, you are talking 3 years bare minimum, more like five. During that time you would need Tesla to hit pause, have no further improvements, and fail to grab market share.
Elon isn't kidding about the potential for autonomy AND the laughable value proposition for manual cars in a post-autonomy world.