I will definitely bookmark this as a nice replacement for "lying".
Consider that in the past plenty of other people in the industry have underestimated things that he's overestimated, such as the potential for reusable rockets and the timeline for electric cars becoming viable. And those have been incredible success stories for him, despite his initial overestimation, which really was overestimation, that many called stupid at the time. And AI may yet turn out that way too. Even if he's wildly optimistic about timelines, he may still end up closer to correct than the conservative establishment in the industry which would prefer to see the status quo go on forever, like with disposable rockets and internal combustion engines.
Whether he believes it or not doesn't mean jack. You are still out several thousand dollars for something that doesn't work.
I bet Liz Holmes really truly thought Theranos products were going to work too.