I've always imagined that they thought they were close and it made a good story (and is a great product idea) so the company just kept growing and getting investment.
But at some point it became clear that it didn't work and either it was an 'emperor's new clothes' situation and they bought their own hype, hubris that they would come through before they were caught, or they were just desperately putting on a facade hoping that they would get it fixed before it all fell apart.
At this point I'm starting to wonder if we'll ever find out exactly which of those situations applied.
I'm assuming they didn't set out to defraud people or cause problems, they ended up in over their heads.