Talking of FSD beta here, I don't think there has been any death or even major accident to date. But that's mostly because (especially until a few months ago) it was bad enough that nobody would trust it, so people were always alert to intervene.

If you were to let FSD beta just drive by itself enough time, and intentionally never intervene, it would eventually crash, no doubt about it. Before v10.69 it was hard to get a 20 minute drive with no interventions (unless it was mostly straight roads).