Tesla worked as long as it had a technological advantage on its competitors (and when its competitors didn't exist at all). Now that the technology went mainstream and the competition is Chinese (high tech & high quality, much cheaper) there is no reason for consumers to choose an American brand. Also, Musk (at least the one that started Tesla and SpaceX, don't know now) isn't someone who's interested in competing in a mature market. I guess that's also the reason for pivoting to humanoid robots: gives him the type of extreme stimulus he needs to keep going.