The point is Elon knows exactly whether estimates are achievable or not, but does it anyways.

There is a reason why legally Autopilot/FSD is a driver-assist system, but for marketing purposes robotaxis are just around the corner.

There is a fine line between 'overly optimistic' and misleading, and more often than not, Elon crosses the line.

See https://elonmusk.today/ for an overview (if a bit biased).