Tesla is ending production of its Model S and X vehicles, with CEO Elon Musk stating that it's time to bring the programs to an end. The company will use the factory in Fremont, California, to build Optimus humanoid robots instead. Tesla's Model 3 and Y vehicles accounted for 97% of the company's deliveries last year, making the S and X less necessary. The decision comes as Tesla reported its first annual revenue decline on record.