I fully believe Elon and Jim Keller truly thought the deep learning HW delivered by Tesla was capable of self-driving in the early 201x time frame because, frankly, a lot of us did. More than likely, like the rest of us, they slowly came to see that the problem was much more difficult, and deep learning much less capable, than we had originally envisioned. Most of us didn't make a bunch of stupid promises to shareholders based on the original, incorrect assumptions though. Unlike Elon, we're able to admit we were wrong.