Not all preorders are fraud.
For fraud, generally you want to show that someone:
(1) falsely represented some material fact, (2) knew it was false, (3) intended for the victim to rely on it; and then the victim (4) reasonably relied on it and (5) was injured.
It's probably the case that some crowdsourced ventures are deceptive, but preorder is a fairly common practice---phones and video games, for example. However, an example that's closer to your question is aviation, where aircraft preorders are frequently funded to incentivize particular features or timelines.