Elon Musk’s unveiling of self-driving taxi prototypes let down some Tesla Inc. investors, with many expecting more particulars on how the carmaker can possibly pull off his latest robocar predictions.

Tesla plans to launch fully autonomous driving in Texas and California next year, with the Cybercab production by 2026 — although he said it could be as late as 2027. Additionally, Tesla is developing the Optimus robot, which could be available for $20,000-$30,000, and is capable of performing various tasks.

Autonomous taxis are already operating on US streets, while Elon Musk has spent years promising a self-driving car and failing to deliver. The newly announced Tesla Cybercab is unlikely to change that