Key TakeawaysTesla shares sank Friday, the morning after its "Cybercab" robotaxi was unveiled at its "We, Robot" event.The electric vehicle maker also revealed a larger "Robovan" and showcased its Optimus humanoid robot.Analysts had said prior to the event that they expected Tesla could announce a lower-cost vehicle to be released next year, but the company did not mention one. Tesla (TSLA) shares stumbled Friday morning as markets appeared to be initially unimpressed with the electric vehicle (EV) maker's ...