Later they happily poured lots of millions into Magic Leap.

Yeah, I was referring to profitability, which, for a for profit company (and one that wants to attract investments), should be part of the core vision, and without which there's no product (just something akin to "selling" $10 bills for $5).

That said, wouldn't all the "pivoting" companies prove that nobody there knew how to achieve their core product vision?

UBeam might very well flameout but I think if you are evaluating a company for fraud potential, there’s no evidence of UBeam making up complete BS to raise investments. In that case, even if their tech doesn’t pan out, as long as they weren’t massively deceiving investors, it would be a failed startup, not a fraudulent one. They are not the same thing.