"How quickly can we get this into people's hands? If you read the papers, you see maybe it's three years, maybe it's thirty years. And I am here to tell you that honestly, it's a bit of both."

This statement is based on what he is aware of at the time. The most pessimistic side of it is purely a data game, and Tesla's ability to have 100k cars collecting data for them will give them a significant advantage to accelerate their progress.