For all of Elon Musk's faults and foibles, even his skeptics would have to agree that he has consistently delivered some game-changing innovations like a commercially viable and appealing electric vehicle (EV), rockets that fly to space for cheaper, and innovations in autonomous vehicles (AV).

At Tesla's (TSLA  ) Robotics and AI day, the company finally unveiled a prototype of the Optimus robot which Musk had previously announced in 2021. The company hopes to begin production later this year and sell it for $20,000.

According to Musk, the robot will be able to complete manual tasks including helping with domestic tasks like cooking and cleaning. He also believes that the robot could eventually become a bigger source of revenue for the company than its cars. It also integrates the same artificial intelligence (AI) technology that is used by the company's full self-driving (FSD) cars.

However, at the unveiling, the robot completed much less impressive tasks like walking and waving to the audience. Further, they also showed a video of the robot watering plants, carrying things, and doing work in the Tesla factory. Yet, these are much less impressive than other feats accomplished by robots made by companies like Boston Dynamics whose robots are able to do acrobatic feats and are widely shared on social media.

At the event, Musk said, "Our goal is to make a useful humanoid robot as quickly as possible. There's still a lot of work to be done to refine Optimus and prove it." Investors didn't seem too enthused by the presentation as the stock was down about 8% on the day.

One factor was that Musk didn't give too much additional insight into Tesla's full self-driving progress. And while Musk made bold promises about the potential of the Optimus, investors have learned their lesson that he is often right about the endgame but notoriously wrong about the timing.

For instance, he has promised in the past that full self-driving would be available to drivers by 2022, but this seems far from fruition. He also promised 1 million robotaxis on the road by 2020, but the company is nowhere near this goal.