To go by the board means to fail, go to waste, or cease to exist, but in this sentence his promise thrived and succeeded
Context: He had promise once, more than I let him know, but he let it all thrive and succeed in a flamboyant quest for his own personal grail.
Hypothesis: He had promise once, more than I let him know, but he let it all go by the boards in a flamboyant quest for his own personal grail.

Given this context, is the hypothesis true (Yes/No/I don't know)?