"Fairly insignificant" just means it's not the talk of the day, by definition. People here appear to be claiming that these big adventures would warrant talking about. That the talk never takes place on screen is proof of one thing only - that V'Ger was less important to them than WWII is to us, by sheer weight of dialogue statistics (every week, a discussion here brings up WWII whilst the Great Recession or any given Summer Olymics pop up fairly seldom). But it cannot be used as proof that umpteen other incidents as big as or possibly bigger than V'Ger didn't also take place, unrelated to anything we saw onscreen, and unrelated to any of the heroes.
Wholly separately, there are incidents where hero set B speaks of an adventure identical to one experienced by hero set A without mentioning hero set A, or even outright denying knowledge of hero set A (as in "Where Silence Has Lease", say). That could be used as proof that A and B exist in different universes altogether, as otherwise their common employer would insist on B knowing about A. But again we can ignore this if we assume that both A and every other letter of alphabet back then had zillions of adventures, too many for B to memorize (even when their very lives depend on them remembering).
Timo Saloniemi
Wholly separately, there are incidents where hero set B speaks of an adventure identical to one experienced by hero set A without mentioning hero set A, or even outright denying knowledge of hero set A (as in "Where Silence Has Lease", say). That could be used as proof that A and B exist in different universes altogether, as otherwise their common employer would insist on B knowing about A. But again we can ignore this if we assume that both A and every other letter of alphabet back then had zillions of adventures, too many for B to memorize (even when their very lives depend on them remembering).
Timo Saloniemi