Tesla's co-founder and former technology chief, J.B. Straubel, discussed his journey at Tesla and his decision to leave in 2019 during a recent interview. He returned to Tesla as a board member earlier this year. Straubel highlighted the initial skepticism Tesla faced and the challenges of scaling the company profitably. He also dismissed concerns about over-investment in lithium-ion battery technology, emphasizing the need for continuous investment in the supply chain, refining processes, infrastructure, and product development.