Why?
Shouldn't the 'holy grail' in astronomy be finding what is there, regardless of what it is?
Science should explore, not for the 7 cities of Cibola, nor El Dorado, but to be like golfers and play it where it lies (and then to work out creative solutions to bad lies)
To specify a 'holy grail' is to set an agenda, like the fools errand of finding, or conjuring, anthropogenic global warming.
I would be laughed out of the seminar if I said the holy grail of all astronomy is to find popsicle sticks. And rightly so.
Shouldn’t the ‘holy grail’ in astronomy be finding what is there, regardless of what it is?
Obviously, you do not comprehend the complexities of modern science wherein scientists look for what they believe they should find and finding receive large financial rewards and prestige, or not finding and receive large financial rewards and prestige.
Amateurs are well advised to stay away from speculating about scientific motives, since there are no large financial rewards and no prestige to be gained. Such a path can only end in major disappointment and sour expressions.