"I don't believe the debates have made a significant impact on voter choice since the first time they were televised in 1960. This year won't be any different"
Not necessarily so.
For example, those who heard the Kennedy-Nixon debate on the radio were convinced that Nixon "won" it hands down. Those who saw it on TV were convinced of the opposite - because of Nixon's propensity to sweat pfrofusely.
Of course, there was this minor issue of about 100,000 questionable votes in Chicago that ultimately decided it.
Reagan was still trailing Carter in the polls until after their final debate. Reagan went on to win in an electoral college landslide.