Do you have evidence to support your first sentence? Jon Stewart influenced the shit out of Congress to pass the PACT Act nowhere near Election Day.
Individual voters are never going to have influence on candidates for office with hundred of thousands of constituents (Wyoming's "at large" Congressman represents around 450,000).
Influence groups, on the other hand, can work for long periods of time to build relationships with elected officials and other groups and media to put show, continuous pressure on. Jon Stewart's work is a case in point.
Cohesive, identifiable, visible groups of voters, as well, can exert pressure. Such as the "uncommitted" campaign in Michigan. But only because they were cohesive and identifiable and made themselves visible.
Me skipping a vote for Harris (or Trump) tells that candidate nothing about why I didn't vote for them. Maybe polling data could.