"we shall see"It has several variations, like
"Time will tell"
"History will be the judge"
"Truth will prevail"and such.
This is a pretty lame departing shot, as it basically demonstrate they have *faith* that they will be vindicated eventually, but they don't have any evidence to support their opinion right now, which makes that a BELIEF.
Note definition #2... "based on ... apprehension rather than proof".
That's exactly what happened here... they have only their own apprehension of how the scheme will make them rich, rather than actual proof. It's religious, rather than evidence-based.
The fact that many scheme promoters behave in a religious fashion have lead to cult experts in calling such schemes "commercial cults".